Solid-state lithium battery
Solid-state lithium battery is increasingly regarded as the "holy grail" of energy storage technology, and is expected to revolutionize multiple industries from electric vehicles to grid energy storage. Compared with traditional lithium-ion batteries, solid-state batteries use solid electrolytes instead of flammable liquid electrolytes, which fundamentally improves the safety performance of batteries. At the same time, by being compatible with high-energy-density electrode materials, it is expected to increase the energy density to 2-3 times that of traditional batteries. This article will comprehensively analyze the technical principles, core advantages, current R&D challenges and commercialization paths of solid-state batteries, and reveal how this disruptive technology will reshape the future energy storage landscape. From breakthroughs in material science to manufacturing process innovations, from laboratory prototypes to mass production and installation, we will track the entire process of solid-state batteries from concept to reality, and look forward to its application prospects in power batteries, aviation transportation, smart grids and other fields.
1. Overview of solid-state battery technology
Solid-state lithium batteries represent a fundamental innovation in battery technology. Its core feature is that solid electrolytes completely replace liquid electrolytes and diaphragms in traditional lithium-ion batteries. This structural change has brought about a qualitative leap in battery performance, making solid-state batteries the next generation of battery technology development direction recognized by academia and industry. Similar to traditional lithium-ion batteries, solid-state batteries are also composed of three major parts: positive electrode, negative electrode and electrolyte. Their working principle is still based on the reversible deintercalation process of lithium ions between positive and negative electrodes. However, the introduction of solid electrolytes has completely changed the internal environment and working mechanism of the battery, providing a new path to solve key problems such as energy density bottlenecks and safety risks faced by traditional lithium batteries.
According to the content of liquid components in the electrolyte, solid-state batteries can be divided into two categories: solid-liquid hybrid batteries (semi-solid batteries) and all-solid-state batteries. Solid-liquid hybrid batteries retain a small amount of electrolyte (usually the liquid electrolyte content is less than 10%), which can effectively alleviate the solid-solid interface contact problem. At the same time, they have significantly improved safety and energy density compared with traditional liquid batteries, and have the potential to be the first to be commercialized. Data show that in the first half of 2024, my country's solid-liquid hybrid batteries have achieved a cumulative installed capacity of 2154.7MWh, indicating that this transition technology has begun to be applied on a large scale. All-solid-state batteries do not contain any liquid electrolytes at all. In theory, they have higher safety and energy density, but they face more severe technical challenges, especially the solid-solid interface impedance problem.
The material selection of solid electrolytes is the core of solid-state battery technology. There are currently three major technical routes: polymer, oxide and sulfide electrolyte systems. Polymer electrolytes (such as PEO-based materials) have excellent processing performance and are easy to form films. They were the first to achieve small-scale commercial applications, but their low room temperature ionic conductivity limits their wide application. Oxide electrolytes (such as LiPON, LLZO, etc.) have excellent chemical stability and a wide electrochemical window, but their interface stability to the metal lithium negative electrode is poor and they are usually brittle. Sulfide electrolytes (such as LiGPS, etc.) show the highest room temperature ionic conductivity (close to or even exceeding that of liquid electrolytes), becoming the most promising technical route at present, but they face challenges such as sensitivity to air and interface stability with electrode materials.
From the perspective of battery structure design, solid-state batteries can be divided into two main forms: thin-film type and large-capacity type. Thin-film solid-state batteries are only a few microns thick and are particularly suitable for microelectronic devices and consumer electronics applications; while large-capacity ones are aimed at scenarios that require high energy storage, such as electric vehicles and grid energy storage. The flexibility of this structural design is difficult for traditional liquid batteries to achieve, enabling solid-state batteries to meet a wide range of application needs from microsensors to grid-level energy storage.
The rapid development of solid-state battery technology is driving the entire energy storage industry into a new stage. With the advancement of materials science and the maturity of manufacturing processes, solid-state batteries are expected to gradually achieve a leap from laboratory to industrialization in the next 5-10 years, bringing revolutionary changes to the field of energy storage.
2. Core advantages of solid-state batteries
Compared with traditional liquid lithium-ion batteries, solid-state lithium batteries have shown all-round performance breakthroughs, and their advantages are mainly reflected in key indicators such as safety, energy density, cycle life and temperature adaptability. These advantages are not incremental improvements, but qualitative leaps, enabling solid-state batteries to meet application needs that current lithium battery technology cannot achieve. From electric vehicles to air transportation, from consumer electronics to grid energy storage, the excellent performance of solid-state batteries is opening up new market space and application scenarios.
Revolutionary safety performance
Safety is one of the most prominent advantages of solid-state batteries and the core driving force behind their development. Traditional liquid lithium batteries have serious safety hazards due to the use of flammable organic electrolytes, and fire and explosion accidents caused by thermal runaway of batteries are common. Solid-state batteries use non-flammable, non-corrosive, and non-volatile solid electrolytes, which fundamentally eliminate the risks of electrolyte leakage and combustion and explosion. Experimental data show that solid-state batteries exhibit extremely high stability under extreme conditions (such as needle puncture, extrusion, and high temperature), and the risk of thermal runaway is reduced by about 80% compared with traditional lithium batteries. This feature is particularly important for electric vehicles and aviation applications, where battery failure may lead to catastrophic consequences.
Solid-state electrolytes can also effectively inhibit the growth of lithium dendrites, which is another major safety hazard of traditional lithium batteries. In liquid batteries, lithium dendrites may pierce the diaphragm and cause internal short circuits, while solid-state electrolytes have higher mechanical strength and can physically block dendrite penetration. In addition, solid-state batteries do not need to worry about the accumulation of gas produced by the decomposition of electrolytes, further improving their safety and reliability. These safety advantages make solid-state batteries particularly suitable for applications with strict safety requirements, such as aircraft, medical equipment, and underground mining equipment.
Breakthrough energy density
Energy density is another key indicator for measuring battery performance, and solid-state batteries also show great potential in this regard. Theoretical predictions and laboratory data show that the energy density of all-solid-state lithium batteries can reach 2-3 times that of traditional lithium-ion batteries, and the maximum energy density can reach 400-500Wh/kg. This leap mainly comes from three aspects: First, solid-state electrolytes have a wider electrochemical window and are compatible with high-voltage positive electrode materials (such as 5V-level positive electrodes) and metal lithium negative electrodes (theoretical specific capacity 3860mAh/g), thereby greatly improving the operating voltage and capacity of the battery; second, solid-state batteries can simplify or eliminate inactive components such as diaphragms, and increase the proportion of active materials in the battery; third, the density of solid-state electrolytes themselves is usually higher than that of liquid electrolytes, which helps to reduce the volume of the battery.
Practical application cases have proven this advantage: the energy density of the all-solid-state battery prototype developed by Tailan New Energy using a lithium-rich manganese-based positive electrode has reached 720Wh/kg; and the energy density of Qingdao Zhongke Yuanben's second-generation solid-state lithium-sulfur battery exceeds 600Wh/kg, and its third-generation product target is set at 800Wh/kg. In comparison, the energy density of the most advanced liquid lithium battery is about 250-300Wh/kg, which is close to its theoretical limit of 350Wh/kg. The high energy density of solid-state batteries will directly translate into improved performance of terminal products - the battery life of smartphones can be extended by 40-60% while reducing weight by more than 15%; the range of electric vehicles is expected to exceed the 1,000-kilometer mark.
Excellent cycle life and temperature adaptability
Solid-state batteries also perform well in terms of cycle life. In traditional liquid batteries, the side reaction between the electrolyte and the electrode material will form a solid electrolyte interface film (SEI), resulting in continuous consumption of active substances and electrolytes, and a decrease in coulombic efficiency. Solid electrolytes have high chemical stability and can effectively inhibit these side reactions. Laboratory data show that all-solid-state batteries using LIPON electrolytes can achieve 45,000 cycles under ideal conditions; the sulfide all-solid-state battery developed by Zhongke Solid Energy has no obvious capacity decay after 24,000 cycles at a 20C rate, showing an ultra-long service life. This ultra-long cycle life is particularly important for grid energy storage and industrial applications, and can significantly reduce the cost of the entire life cycle.
Solid-state batteries also have a wider operating temperature range (-25°C to 60°C), overcoming the problem of rapid performance decay of traditional lithium batteries at extreme temperatures. This feature enables solid-state batteries to adapt to various climatic conditions from polar regions to deserts, as well as special environmental requirements such as aerospace. It is particularly worth mentioning that the lithium manganese oxide positive electrode, combined with a solid electrolyte, performs better than the current mainstream lithium iron phosphate battery under low temperature conditions, providing an ideal choice for applications in cold regions.
These outstanding properties of solid-state batteries do not exist in isolation, but are mutually reinforcing. For example, higher safety allows the battery system to be designed more compactly, further improving energy density; a wider temperature range enables the battery to maintain stable cycle performance in various environments. This overall improvement in performance is redefining the boundaries of what is possible in battery technology, bringing truly revolutionary changes to the field of energy storage.
3. Key challenges of solid-state batteries
Although solid-state batteries have shown great potential in performance, they still face multiple technical barriers in their transition from laboratory to large-scale commercialization. These challenges involve multiple dimensions such as material science, interface engineering, manufacturing process and cost control, and constitute the hurdles that must be overcome on the road to solid-state battery industrialization. A deep understanding of the nature of these challenges and possible solutions is crucial to grasping the development context and commercial prospects of solid-state battery technology.
Solid-solid interface problem
The interface problem is one of the most core challenges facing solid-state batteries. In traditional liquid batteries, liquid electrolytes can form good contact with electrode materials to ensure efficient transmission of lithium ions. In solid-state batteries, the solid-solid contact between solid electrolytes and electrode materials is difficult to achieve the same degree of closeness, resulting in higher interface impedance. This problem will be further exacerbated during the cycle process, because the volume change of electrode materials will cause interface contact failure. Wu Fan, chairman of Zhongke Solid Energy, pointed out: "In all-solid-state batteries, the interface stability between electrodes and solid electrolytes is crucial to battery performance. How to build a relatively stable solid-solid interface is a challenge in technological development."
Solving the interface problem requires a multi-pronged approach: on the one hand, it is necessary to develop solid electrolyte materials with good flexibility and elasticity to adapt to the volume change of electrode materials; on the other hand, the interface needs to be chemically modified, such as in-situ surface treatment or the introduction of ultra-thin interface layers, to enhance interface compatibility and ion transfer efficiency. In addition, the battery assembly process is also crucial. Appropriate pressure treatment can improve the initial interface contact, but the relationship between the pressure size and the integrity of the battery structure needs to be balanced.
Comprehensive performance balance of electrolyte materials
The material selection of solid electrolytes is itself a complex technical problem. An ideal solid electrolyte needs to meet multiple requirements such as high ionic conductivity, chemical stability to electrode materials (especially metal lithium anodes), wide electrochemical window, good mechanical properties, and low cost. However, no material can currently meet all these conditions perfectly:
Although sulfide electrolytes have the highest ionic conductivity (close to liquid electrolytes), they are extremely sensitive to air and moisture, and production needs to be carried out in a strictly controlled dry environment, which greatly increases the manufacturing cost and process complexity. Oxide electrolytes have good chemical stability but are usually brittle, making it difficult to form good contact with electrodes, and have low room temperature ionic conductivity. Polymer electrolytes have excellent processing performance but a narrow electrochemical window, making them difficult to be compatible with high-voltage positive electrode materials, and their room temperature conductivity is insufficient.
Faced with this dilemma, researchers are exploring composite electrolyte strategies to combine the advantages of different types of electrolyte materials. For example, filling oxide particles into a polymer matrix can simultaneously improve ionic conductivity and mechanical strength; or constructing a multilayer electrolyte structure to optimize interface stability and bulk transport performance using the characteristics of different materials.
Manufacturing process and scale-up challenges
The production process of solid-state batteries is significantly different from that of traditional liquid batteries, and faces unique scale-up challenges. The core link in solid-state battery manufacturing is the solid electrolyte film-forming process, and its quality directly affects battery performance and reliability. At present, there are two main process routes for electrolyte film formation: wet and dry processes:
The wet process uses a solvent to make the electrolyte material into a slurry, then coats it into a film, and finally evaporates to remove the solvent. This method is suitable for polymers and composite electrolytes, but there is a risk of solvent residue, which may reduce ionic conductivity. The dry process does not use solvents at all. It directly forms a film through dry mixing, fiberization, granulation and calendering, avoiding the problem of solvent residue. However, the prepared electrolyte membrane is usually thicker, which will reduce the battery energy density.
In the battery assembly process, solid-state batteries usually use the stacking process instead of the winding process commonly used in liquid batteries, because oxide and sulfide electrolytes have poor toughness and are not suitable for winding. The stacking process is divided into two methods: segmented stacking and integrated stacking. The former cuts the positive electrode, electrolyte and negative electrode separately and stacks them, while the latter first rolls them into a "positive electrode-electrolyte-negative electrode" three-layer structure and then cuts and stacks them. In either case, the interface contact problem needs to be solved, which places extremely high demands on production accuracy and process control.
In addition, the production of all-solid-state batteries also requires the addition of isostatic pressing equipment and high-pressure chemical component capacity equipment, while eliminating the injection process. According to CITIC Securities analysis, the investment in single GWh all-solid-state battery equipment is as high as 250 million yuan, far higher than the 120 million yuan of liquid batteries and 150 million yuan of semi-solid batteries. This high equipment investment and complex production process constitute an important obstacle to the scale-up of solid-state batteries.
Dendrite problem of lithium metal anode
Although metal lithium anode is the key to achieving high energy density, its application still faces severe challenges of lithium dendrite growth. Even in solid electrolytes, lithium dendrites may still grow along grain boundaries or defect sites, eventually leading to battery short circuit failure. Wu Fan pointed out: "Lithium dendrite growth in all-solid-state batteries may lead to battery failure or safety issues, so controlling the growth of lithium dendrites is an important issue in technological development."
Strategies to address this challenge include: developing solid electrolyte materials with high mechanical strength to physically block dendrite penetration; designing electrolyte layers with gradient structures to homogenize lithium ion flow; and chemically modifying the surface of lithium anode to guide uniform lithium deposition. Zhongke Solid Energy has developed "hard carbon-stabilized lithium silicon anode and soft carbon interface-modified metal lithium anode", and successfully achieved "charge and discharge without lithium dendrite growth at 50C rate".
The need for innovation in the cathode material system
The development of solid-state batteries not only relies on breakthroughs in electrolytes, but also requires collaborative innovation in the cathode material system. Traditional high-nickel ternary cathode materials are close to the energy density limit (about 300Wh/kg), which is difficult to meet the needs of the next generation of batteries. The promotion of solid-state batteries is giving rise to a "reshuffle" in the field of cathode materials, and new cathode materials such as manganese and sulfur are expected to take over the current LFP and ternary materials.
Sulfur-based cathodes (such as lithium sulfide and elemental sulfur) have extremely high theoretical specific capacity (1675mAh/g), and are expected to achieve an energy density of 600-800Wh/kg when combined with solid-state electrolytes. Qingdao Zhongke Yuanben's solid-state lithium-sulfur battery still maintains 84.4% of its initial capacity after 6,200 cycles at room temperature, showing good cycle stability. Manganese-based materials (such as lithium-rich manganese-based, nickel-manganese-oxide lithium, etc.) have attracted attention due to their high voltage platform, abundant resources and low cost advantages. Qingtao Energy has launched a 20,000-ton lithium manganese-oxide cathode material project.
However, these new cathode materials also face their own challenges: sulfur-based cathodes have poor electronic conductivity and polysulfide shuttle effects; lithium-rich manganese-based materials have problems such as low compaction density and voltage attenuation. Solving these problems requires material-level modification (such as carbon coating, element doping) and coordinated optimization of battery design (such as cathode-electrolyte interface engineering).
Faced with these multi-dimensional challenges, the industry is adopting an incremental development strategy, gradually transitioning from solid-liquid hybrid batteries to all-solid-state batteries, and solving technical problems in stages. This path is in line with the laws of technological development and can continuously accumulate experience and funds in the commercialization process, laying the foundation for the ultimate realization of the industrialization of all-solid-state batteries.
4. Innovation in the manufacturing process of solid-state batteries
The industrialization of solid-state batteries not only depends on material breakthroughs, but also requires a comprehensive innovation in manufacturing processes. Compared with traditional liquid lithium batteries, solid-state batteries have significant differences in production processes, equipment requirements and process parameters. These manufacturing challenges are directly related to whether solid-state batteries can achieve large-scale mass production and cost control. A deep understanding of the unique process routes and technical difficulties of solid-state battery manufacturing is crucial to grasping its commercialization process.
Core differences in solid-state battery manufacturing
Solid-state batteries and liquid batteries have both continuity and revolutionary changes in manufacturing processes. Continuity is reflected in the front-end electrode manufacturing link - the preparation of positive and negative electrode sheets is still based on similar processes such as slurry mixing, coating and rolling. However, solid-state battery manufacturing is essentially different from traditional processes in three key aspects:
First, solid-state batteries use a composite positive electrode structure, that is, solid electrolyte particles and positive electrode active materials are evenly mixed to form a composite positive electrode material, which requires the development of a new slurry formula and mixing process. Secondly, the way electrolytes are added is completely different - liquid batteries inject electrolytes after the battery cells are assembled, while solid-state batteries require the electrolytes to be made into thin films and precisely integrated into the electrode structure. Third, due to the brittle nature of solid electrolytes, solid-state batteries can usually only adopt a laminated structure design, and cannot use the winding process commonly used in liquid batteries.
These fundamental differences lead to the need for a large number of special equipment and process innovations in the production of solid-state batteries. According to CITIC Securities Research, the investment in single GWh all-solid-state battery equipment is as high as 250 million yuan, far higher than the 120 million yuan of liquid batteries, among which the value and proportion of front-end equipment have increased significantly. This high equipment investment is one of the important reasons for the high cost of solid-state batteries.
Solid-state electrolyte film formation process
Electrolyte film formation is the most critical and challenging link in the manufacture of solid-state batteries, which directly affects the energy density, cycle life and safety performance of the battery. The thickness and uniformity of the solid electrolyte film need to be precisely controlled - too thin will lead to insufficient mechanical strength and easily cause internal short circuits; too thick will increase internal resistance and reduce energy density. At present, the main film-forming processes can be divided into three categories: wet process, dry process and special deposition method:
The wet film-forming process draws on the coating technology of traditional lithium batteries, disperses the solid electrolyte powder in the solvent to form a slurry, and then forms an electrolyte membrane by coating and drying. According to the different supports, the wet process can be divided into three methods: mold support film-forming (applicable to polymers and composite electrolytes), positive electrode support film-forming (applicable to inorganic and composite electrolytes) and skeleton support film-forming (enhanced mechanical strength). The advantage of the wet process is that it can prepare a thin and uniform electrolyte layer and is partially compatible with existing coating equipment; but its core challenge lies in the selection of solvents-the solvent must be easy to evaporate, have good solubility in the electrolyte and be chemically stable, and residual solvents will significantly reduce ionic conductivity.
The dry film-forming process does not use solvents at all, and directly prepares the electrolyte membrane through steps such as dry mixing, fiberization, granulation and calendering. The dry process avoids the problem of solvent residues and the equipment is relatively simple, but the prepared electrolyte membrane is usually thicker (50-100μm), which will reduce the energy density of the battery. In addition, the dry process has high requirements for the morphology and particle size distribution of electrolyte materials, and it is difficult to achieve ultra-thin uniform film formation. However, with the advancement of dry technology, its low cost and pollution-free advantages are making it a potential mass production process route.
Special deposition processes include high-precision film formation technologies such as chemical vapor deposition (CVD), physical vapor deposition (PVD), electrochemical deposition and vacuum sputtering. These methods can prepare electrolyte films with precise and controllable thickness (as low as a few microns) and excellent uniformity, which are particularly suitable for thin-film all-solid-state batteries. However, the deposition process equipment is expensive and the production efficiency is low. It is currently mainly used for laboratory research and small-batch special applications, and it is difficult to meet the large-scale production needs of power batteries.
Different types of solid electrolytes need to match the appropriate film formation process: polymer electrolytes have the best processing performance and can be processed by dry rolling, extrusion, casting and other processes; sulfide electrolytes are sensitive to air and are not suitable for high-temperature processing, and mainly use rolling and spraying; oxide electrolytes usually require a combination of particle deposition and sintering to form a film. This material-process matching relationship is one of the core contents of the development of solid-state battery manufacturing technology.
Innovation in cell assembly process
The cell assembly process of solid-state batteries is significantly different from that of traditional liquid batteries. Due to the characteristics of solid electrolytes, the winding process is no longer applicable, and lamination becomes the mainstream choice. The lamination process is divided into two main forms:
The segmented lamination process follows the lamination method of liquid batteries, stacking the pre-cut positive electrode, solid electrolyte membrane and negative electrode in sequence. This method is mature, but the alignment accuracy is high and the lamination efficiency is relatively low. The integrated lamination process is more advanced. The positive electrode, electrolyte and negative electrode are first rolled into a three-layer composite structure, and then cut and stacked. This method improves production efficiency, but the interface bonding problem of multi-layer composite structures needs to be solved.
Regardless of the lamination method used, solid-state batteries usually need to be pressurized (such as isostatic pressing) after assembly to improve solid-solid interface contact. This step is particularly important for oxide and sulfide batteries, but the pressurization lasts for a long time (may be several hours), which becomes a bottleneck in production cycle. In addition, the formation process of solid-state batteries also needs to be carried out under higher pressure, which puts new requirements on the formation and capacity equipment.
It is worth noting that the production of solid-state batteries eliminates the injection process in liquid batteries, simplifies the subsequent process, but also loses the "self-healing" effect of the electrolyte on the interface. This means that solid-state batteries have higher requirements for manufacturing precision, and any interface defects may cause battery performance degradation or failure.
Co-optimization of materials and processes
Solid-state battery manufacturing is not an isolated process, but requires deep coordination with the material system. For example, sulfide electrolytes are extremely sensitive to moisture, requiring the humidity of the production environment to be controlled at the ppm level, which greatly increases the cost of plant and equipment. Although oxide electrolytes have good environmental stability, they are highly brittle and require optimized electrode structure design to avoid fracture. Polymer electrolytes need to be processed at a specific temperature to maintain appropriate ionic conductivity.
The electrode formula also needs to be adjusted accordingly: a large amount of solid electrolyte (30-50% volume ratio) is usually required to be added to the positive electrode of solid-state batteries to construct a continuous ion transmission channel, which reduces the energy density of the positive electrode. To solve this problem, researchers have developed a three-dimensional electrode structure that infiltrates the electrolyte into the porous electrode as a skeleton, which not only ensures the ion transmission path, but also increases the proportion of active substances.
In addition, the choice of manufacturing process for solid-state batteries is also affected by the target application scenario: small solid-state batteries for consumer electronics may use high-precision deposition processes to achieve ultra-thin design; while large-capacity batteries for vehicles need to consider mass production feasibility and cost, and tend to choose wet or dry film-forming processes. This differentiated development path makes solid-state battery manufacturing technology present a diversified pattern.
Challenges of transformation of equipment and production lines
The industrialization of solid-state batteries faces huge challenges of equipment transformation. Traditional lithium battery production lines cannot be directly used for solid-state battery production and require major transformation or complete replacement. According to CITIC Securities analysis, the main changes in solid-state battery production equipment include:
In the front-end process, dry equipment (including dry mixing equipment, fiberization equipment, granulation equipment and film-forming equipment) will gradually replace wet equipment, and electrolyte thermal composite equipment will be added. Rolling equipment needs to undertake multiple functions such as film formation, thermal composite, and negative electrode lithium replenishment, and the technical requirements and value have been significantly improved. In the middle and back-end processes, the injection equipment is cancelled, the winding machine is replaced by the stacking equipment, and new equipment such as isostatic pressing equipment and high-pressure chemical component capacity equipment are introduced.
These equipment changes have led to a significant increase in investment in solid-state battery production lines. It is estimated that the investment in single GWh all-solid-state battery equipment is about 250 million yuan, much higher than the 120 million yuan of liquid batteries. The high cost and low maturity of equipment have become one of the main bottlenecks restricting the mass production of solid-state batteries. To meet this challenge, some companies have adopted a gradual strategy, first transforming existing production lines to produce semi-solid-state batteries, and then gradually transitioning to all-solid-state batteries to share investment risks and costs.
With process optimization and economies of scale, the manufacturing cost of solid-state batteries is expected to gradually decrease. Material innovation (such as new positive and negative electrode and electrolyte materials) and process improvement (such as dry film formation and integrated lamination) will be the key path to reducing costs. In addition, the localization and standardization of equipment will also provide important support for the industrialization of solid-state batteries.
5. Commercialization progress and application prospects
Solid-state battery technology is rapidly moving from laboratory research to industrial application, and a diversified commercialization path has been formed worldwide. Solid-state battery products with different technical routes and different application scenarios are gradually entering the market, showing the broad prospects of this technology. Analyzing the current commercialization progress and future application trends will help to accurately grasp the development pulse and investment opportunities of the solid-state battery industry.
Current commercialization progress
Solid-liquid hybrid batteries (semi-solid-state batteries) have taken the lead in commercial application as a transitional technology. In the first half of 2024, the cumulative installed capacity of solid-liquid hybrid batteries in China has reached 2154.7MWh, indicating that this technical route has the ability to be applied on a large scale. In the field of electric vehicles, SAIC Group is at the forefront - the L6 model launched by its Zhiji brand is equipped with the "Light Year Solid-State Battery 1.0" (actually a semi-solid-state battery with a liquid content of 10%), which supports 400kW ultra-fast charging and can increase the range by 400 kilometers in 12 minutes. SAIC plans to launch a battery with a liquid content of 5% in 2025 and mass-produce all-solid-state batteries in 2026, showing a clear technology roadmap.
The energy storage field has also witnessed the early commercialization of solid-state batteries. At the beginning of 2025, China launched three major solid-state battery energy storage project biddings, with a total demand of more than 412MWh, including Huadian Digital Intelligence Buliangou Coal Mine 4.5MW/9MWh semi-solid energy storage system, Tai'an Feicheng 100MW/400MWh solid-state lithium battery energy storage project, etc. According to statistics, the total demand for solid-state battery energy storage procurement has been close to 1GWh since 2024, indicating that this technology is accelerating its implementation.
In the low-altitude economy, solid-state batteries have become an ideal choice for electric vertical take-off and landing aircraft (eVTOL) due to their high energy density and safety. Ehang Intelligent has completed the first flight of solid-state batteries, and the cooperation between CATL and Fengfei Aviation also focuses on the application of solid-state batteries. The industry predicts that by 2025, eVTOL will gradually transition to semi-solid batteries, and by 2031, the eVTOL battery market size will reach 10 billion yuan.
Globally, Toyota of Japan maintains a leading position in the field of sulfide solid-state batteries, with more than 30 core patents, and plans to achieve commercialization after 2025. European and American companies such as QuantumScape and Solid Power focus on oxide and polymer routes, and have in-depth cooperation with automakers such as Volkswagen and BMW. Chinese companies such as Qingtao Energy and Weilan New Energy have adopted a solid-liquid hybrid gradual route and have achieved mass production and installation of semi-solid batteries.
Phased commercialization path
The commercialization of solid-state batteries presents a clear and gradual development feature. Ouyang Minggao, an academician of the Chinese Academy of Sciences, pointed out: "The time when solid-state batteries are truly put into large-scale commercial application is probably between 2025 and 2030." This process will be promoted in three stages:
The first stage (2020-2025) is mainly based on solid-liquid hybrid batteries, and the liquid electrolyte content will gradually decrease from 10% to 5%, mainly solving basic scientific problems and key material breakthroughs. The application scenarios in this stage are concentrated in high-end electric vehicles (such as SAIC Zhiji, NIO ET7, etc.) and special energy storage fields. The product premium is high, the market size is limited but growing rapidly.
The second stage (2025-2030) will achieve small-scale mass production of low-liquid content (<5%) or even all-solid-state batteries, focusing on breaking through the bottlenecks of manufacturing processes and costs. The application scenarios will be expanded to mainstream electric vehicles, air transportation and grid energy storage, and the market penetration rate will increase rapidly. CITIC Securities predicts that by 2030, global solid-state battery shipments will reach 556GWh, of which about 251GWh will be in China, mainly solid-liquid hybrid batteries, and the penetration rate of all-solid-state batteries may be less than 1%.
The third stage (after 2030) will usher in the large-scale application of all-solid-state batteries, the material system and manufacturing process will become mature, and the cost competitiveness will be significantly improved. Wu Fan of Zhongke Solid Energy predicts: "By 2030, the penetration rate of all-solid-state lithium batteries in the electric vehicle market will increase significantly, and the market size is expected to achieve explosive growth." At this stage, solid-state batteries are expected to gradually replace liquid lithium batteries in high-end application fields, forming a new industrial pattern.
It is worth noting that different application fields will show differentiated commercialization rhythms. Small battery applications such as consumer electronics and special equipment may be the first to adopt all-solid-state technology; while large-capacity applications such as electric vehicles will follow a gradual path from hybrid to all-solid-state. This differentiated development is determined by the different trade-offs between performance, cost and reliability in various fields.
Diversified application prospects
The excellent performance of solid-state batteries has opened up a wide range of application scenarios for them, from portable electronic devices to grid-level energy storage, from ground transportation to aerospace. These applications not only expand the boundaries of battery technology, but also create new market opportunities.
Electric vehicles are undoubtedly the most important application field of solid-state batteries. The high energy density of solid-state batteries can increase the range of electric vehicles to more than 1,000 kilometers, while also significantly improving fast charging capabilities and safety. Mainstream car companies such as SAIC, Toyota, and BMW have deployed solid-state battery models, and it is expected that there will be a intensive listing wave from 2025 to 2030. It is particularly noteworthy that solid-state batteries may change the design paradigm of electric vehicles - higher safety allows for more compact battery pack designs, bringing new possibilities for vehicle space layout.
The aviation transportation field, especially eVTOL and electric aircraft, has extremely strict requirements on battery energy density and safety, making it a natural application scenario for solid-state batteries. At present, the energy density of lithium batteries used in eVTOL is only 200-300Wh/kg, which severely limits the range and load; while solid-state batteries are expected to provide an energy density of more than 400Wh/kg in the short term, opening up a new situation for electric aviation. The industry predicts that by 2026, domestic host manufacturers will usher in intensive certification, which will promote the demand for solid-state batteries in the aviation field.
Grid energy storage is another important application direction of solid-state batteries. Although the current cost is high, the advantages of solid-state batteries such as long life (up to tens of thousands of cycles), high safety and wide temperature range make them particularly suitable for large-scale energy storage applications. The launch of multiple 100MWh solid-state battery energy storage projects in early 2025 shows that this market has begun to start. With the emergence of economies of scale and the decline in costs, solid-state batteries are expected to occupy an important share in the high-end energy storage market.
In the field of consumer electronics, the thinning capability (several microns thick) and high energy density of solid-state batteries will provide revolutionary power solutions for wearable devices, flexible electronics, etc. Although the mass production of all-solid-state thin-film batteries still faces challenges, once a breakthrough is made, it will completely change the design concept and user experience of consumer electronic products.
Special applications such as power demand in extreme environments such as deep-sea equipment, polar expeditions, and military equipment are also areas of advantage for solid-state batteries. The "Qingneng I" solid-state battery developed by the Qingdao Institute of Bioenergy of the Chinese Academy of Sciences has been successfully used in deep-sea scientific expeditions, proving its reliability in extreme environments.
Market Forecast and Industry Impact
The growth potential of the solid-state battery market has attracted much attention. According to the "2025-2030 Global and China Solid-State Battery Industry Market Status Survey and Development Prospects Analysis Report" released by China Report Hall, the global solid-state battery market is expected to reach US$50 billion by 2030. This growth will mainly come from strong demand in the three major areas of electric vehicles, air transportation and energy storage.
From the perspective of the industrial chain, the rise of solid-state batteries will trigger a profound change in the battery material system. Traditional cathode materials are facing pressure to upgrade, and new cathode materials such as manganese and sulfur will gradually emerge. Companies such as Qingtao Energy and Sufang New Energy have launched 10,000-ton lithium-rich manganese-based cathode material projects, and Sichuan Chengke Guoxin New Energy has deployed 2.8GWh of solid-state lithium-sulfur battery production capacity. This innovation of the material system will reshape the upstream supply chain pattern.
The equipment field also faces major opportunities. CITIC Securities predicts that the domestic investment in solid-state battery equipment will be close to 20 billion yuan in 2030, among which the value and proportion of front-end equipment will increase significantly. The demand for special equipment such as dry film forming equipment, integrated stacking machines, and isostatic pressing equipment will grow rapidly, bringing new opportunities for equipment manufacturers with technical reserves.
The development of solid-state batteries will also promote cross-innovation. For example, new energy solutions such as hybrid energy storage systems of solid-state batteries and supercapacitors and hybrid power systems of solid-state batteries and fuel cells will gain development momentum. These innovations will further expand the application boundaries of energy technology and accelerate the global energy transformation process.
Overall, although the commercialization of solid-state batteries still faces challenges, the development direction has been clear and the pace of industrialization is accelerating. With the combined effects of material innovation, process improvement and scale effect, solid-state batteries are expected to penetrate from high-end to mainstream markets in the next 5-10 years, and eventually become one of the leading technologies in the field of energy storage. This process will not only change the battery industry landscape, but will also profoundly affect the future development paths of multiple industries such as transportation, power systems, and electronic equipment.
