Future innovations in lithium-ion technology: solid-state batteries and others
Against the global backdrop of climate change and energy transition, energy storage technology has become a key support for achieving the "dual carbon" goal. As the core force in the current energy storage field, lithium-ion battery technology is facing unprecedented innovation opportunities and challenges. In 2024, global lithium-ion battery shipments exceeded 1.3 terawatt-hours, with China accounting for more than 60% of the market. This figure not only reflects the vigorous vitality of the market, but also reveals the urgent need for technological iteration. The energy density of traditional lithium-ion batteries is close to the theoretical limit, safety bottlenecks are becoming increasingly prominent, and resource constraints are gradually emerging. These factors are jointly driving the evolution of energy storage technology to the next generation. This article will explore the innovation frontier of lithium-ion technology in depth, focusing on the most disruptive technical direction of solid-state batteries, while examining the progress and prospects of diversified technical routes such as sodium-ion batteries and lithium metal batteries. From breakthroughs in materials science to engineering challenges, from laboratory research and development to industrial layout, we will comprehensively depict the future of lithium-ion technology and present readers with an ongoing energy storage revolution.
1. Technical limits and incremental innovation of lithium-ion batteries
Today, the lithium-ion battery industry has formed a dual-dominant pattern of "ternary materials" and "lithium iron phosphate". Ternary batteries occupy the high-end electric vehicle market with an energy density of 200-300Wh/kg, while lithium iron phosphate batteries shine in the field of energy storage power stations and mid- and low-end electric vehicles with better safety and cycle life. This technical division reflects the multi-dimensional balance characteristics of lithium-ion batteries in terms of performance dimensions-indicators such as energy density, safety, life, and cost often restrict each other and are difficult to achieve at the same time. According to statistics from the China Automotive Power Battery Industry Innovation Alliance, in 2024, lithium iron phosphate batteries accounted for 68% of my country's installed power battery capacity, while ternary batteries accounted for 31%. This change in proportion highlights the market's increasing attention to safety and economy.
Faced with physical and chemical limits, the industry has not stopped the pace of incremental innovation. In terms of positive electrode materials, high nickel and low cobalt have become the mainstream trend, and the mass production process of high nickel ternary materials such as NCM811 and NCA has gradually matured; breakthroughs have been made in the research of lithium-rich manganese-based positive electrode materials, with a theoretical capacity of more than 300mAh/g, providing possibilities for the next generation of high energy density batteries. In the field of negative electrode materials, the industrialization process of silicon-based negative electrodes has accelerated, and Tesla's 4680 battery has adopted silicon-carbon composite negative electrodes, with a specific capacity of more than 450mAh/g; important progress has been made in the interface regulation technology of lithium metal negative electrodes, and the cycle stability has been significantly improved. The coordinated development of supporting technologies such as electrolyte additives and functional diaphragms enables these innovative materials to maximize their efficiency.
High nickel positive electrode: nickel content increased to more than 90%, cobalt content reduced to less than 5%, reducing costs while increasing energy density
Silicon-based negative electrode: from silicon oxide to nano-silicon-carbon composite, the volume expansion problem is gradually solved
Electrolyte innovation: new lithium salts (LiFSI) and functional additives improve high temperature performance and cycle life
The innovation of manufacturing processes also promotes the performance improvement of lithium-ion batteries. The dry electrode process omits the solvent recovery link in the traditional wet coating process, which not only reduces energy consumption, but also makes it possible to increase the electrode thickness, thereby increasing the volume energy density; the optimization of the stacking process reduces the internal resistance of the battery by more than 10%, and the rate performance is significantly improved; the introduction of intelligent manufacturing technology has greatly improved production consistency and yield rate, and the defect rate of CATL's "Lighthouse Factory" has dropped to one billionth. Although these innovations are incremental, the cumulative effect is significant. It is expected that the energy density of lithium-ion batteries will increase by another 15-20% and the cost will decrease by 30% in the next five years.
The intelligent development of thermal management systems represents an important direction for safety innovation of lithium-ion batteries. The real-time monitoring technology of battery health status (SOH) based on AI algorithms can predict the risk of battery failure dozens of cycles in advance; the composite thermal management system combining phase change materials and liquid cooling can control the temperature difference of the battery pack within 3°C; the application of new thermal insulation materials such as aerogels extends the propagation time of thermal runaway from minutes to hours, winning precious time for the occupants to escape. Although these technological advances cannot fundamentally solve the inherent defect of flammable liquid electrolytes, they significantly reduce the probability of accidents and the degree of harm.
It is worth noting that the resource constraints of lithium-ion batteries are becoming increasingly apparent. The distribution of lithium resources in the world is extremely uneven, with Chile, Australia and Argentina accounting for more than 75% of the proven reserves; cobalt resources are more concentrated, with the Democratic Republic of the Congo supplying more than 70% of the world's production. This geographical concentration brings supply chain risks, and the lesson of the 5-fold surge in lithium prices in 2022 has prompted the industry to seek solutions. Advances in resource recycling technology have partially alleviated this pressure. The current lithium recovery rate has reached more than 90%, and the cobalt and nickel recovery rate has exceeded 95%. In addition, the development of alternative technologies such as low-cobalt and cobalt-free cathode materials and sodium-ion batteries also constitutes a combined strategy for dealing with resource constraints.
The incremental innovation of lithium-ion batteries is still ongoing, but its ceiling effect is clearly visible. Even with the most optimistic estimates, the energy density of traditional liquid lithium-ion batteries is difficult to break through 350Wh/kg, which is difficult to meet the higher demands of application scenarios such as aviation and high-end electric vehicles. At the same time, the fundamental challenge of safety cannot be completely solved through improvements. These limitations have prompted the industry to look at a more disruptive technology direction - solid-state batteries, which are expected to break through the dual bottlenecks of energy density and safety at the same time, and usher in a new era of energy storage technology.
2. Solid-state batteries: opening a paradigm revolution in energy storage technology
Solid-state batteries represent a fundamental breakthrough in lithium-ion technology. Their core feature is to completely replace the liquid electrolyte and diaphragm in traditional batteries with solid electrolytes. This change is by no means a simple material replacement, but involves all-round innovation in electrochemical systems, interface engineering, and manufacturing processes. From the technical principle point of view, solid-state batteries have three advantages: solid electrolytes are non-flammable, which fundamentally solves the risk of thermal runaway; they are compatible with metal lithium negative electrodes, and the theoretical energy density can reach more than twice that of traditional batteries; the wide electrochemical window allows the use of high-voltage positive electrode materials, further pushing up the energy density. These advantages make solid-state batteries the next generation of energy storage technology recognized by academia and industry.
At present, the research and development of solid-state batteries presents a diversified pattern of technical routes, which are mainly divided into three major systems: polymers, oxides, and sulfides, as well as the composite routes derived from them. The polymer solid electrolyte is represented by PEO, which has excellent processing performance but low room temperature conductivity and needs to work at 60-80℃; oxide electrolytes such as LLZO have good chemical stability, but are brittle and have high interface impedance; sulfide electrolytes have the highest room temperature conductivity (10⁻²-10⁻³S/cm), but are sensitive to water vapor and difficult to mass produce. Different routes have their own advantages and disadvantages, and no unified technical standards have been formed. This diversity reflects both the activeness of innovation and the possible differentiation of the industry in the future.
Polymer route: good flexibility, suitable for roll-to-roll production, but the problems of ionic conductivity and oxidation stability need to be solved
Oxide route: excellent stability, thin film process can be used, but the sintering temperature is high and the cost is expensive
Sulfide route: conductivity is close to that of liquid electrolyte, but the production environment is demanding and there are many side reactions at the interface
Composite route: combining the advantages of multiple electrolytes, such as oxide-polymer composites that take into account both performance and processability
The progress of Chinese companies in the field of solid-state batteries is remarkable. The oxide-based solid-state battery developed by Qingtao Energy has achieved an energy density of 360Wh/kg and a cycle life of more than 1,000 times; Weilan New Energy's "semi-solid" battery prepared by in-situ curing technology was first installed in vehicles, achieving a range of 1,000 kilometers on models such as the NIO ET7; the all-solid-state battery research and development roadmap announced by CATL shows that its sulfide system is expected to reach 500Wh/kg in 2027. These achievements mark that China has transformed from a follower of liquid lithium batteries to an innovative leader in solid-state batteries. It is particularly noteworthy that Chinese companies are more active in promoting industrialization and have built multiple pilot lines. This strategy of "giving equal importance to research and development and industrialization" is expected to gain an advantage in future commercial competition.
Interface issues are the biggest scientific challenge facing solid-state batteries. The interface impedance of solid-solid contact far exceeds that of liquid-solid interface, and the volume change of electrodes during the cycle will further deteriorate the contact state. In response to this problem, the scientific research community has proposed a variety of innovative solutions: the Tsinghua University team developed the "interface buffer layer" technology, inserting functional materials between the positive electrode and the electrolyte to reduce impedance; the Institute of Physics of the Chinese Academy of Sciences proposed the concept of "flexible interface", which adapts to volume changes through elastic materials; the patent published by Huawei shows a "three-dimensional interpenetrating network" structure, which greatly increases the contact area. Although these innovations have different angles, they have the same goal - to build a stable, low-resistance ion-electron transmission channel.
Manufacturing process and cost are another major obstacle to the industrialization of solid-state batteries. Compared with traditional lithium batteries, solid-state battery production faces three major challenges: strict environmental control (such as sulfides require a fully inert atmosphere), great process innovation (such as oxides require high-temperature sintering), and strong equipment specificity (such as multi-layer stacking equipment). These factors have jointly pushed up the manufacturing cost. At present, the price of solid-state batteries is about 3-5 times that of traditional lithium batteries. In order to break through this bottleneck, the industry is seeking solutions from multiple dimensions: developing room temperature molding processes to reduce energy consumption, such as dry pressing molding technology; designing new battery structures to simplify manufacturing steps, such as diaphragm-free integrated design; establishing a material recycling system to reduce raw material costs. The industry generally expects that as the technology matures and the scale expands, the cost of solid-state batteries is expected to drop to within 1.5 times of traditional lithium batteries around 2030, reaching the critical point of commercialization.
The industrialization of solid-state batteries will show a phased evolution. From the perspective of electrolyte morphology, it will undergo a gradual process of "liquid → semi-solid → quasi-solid → all-solid"; from the perspective of application scenarios, it will penetrate along the path of "consumer electronics → special fields → high-end automobiles → mass market". From 2024 to 2027, semi-solid batteries will be first used in high-end electric vehicles, aerospace and other fields; from 2027 to 2030, all-solid-state batteries will achieve small-scale mass production; after 2030, as costs decrease and technology improves, they will gradually expand to the mainstream market. This gradual industrialization strategy can effectively control risks while continuously accumulating technology and market experience.
The patent layout reveals the technical competition situation of solid-state batteries. As of 2024, the number of solid-state battery patents worldwide has exceeded 30,000, and China, Japan, South Korea, the United States and Europe have formed a multi-polar competition pattern. Japanese companies have obvious advantages in the field of sulfide electrolytes, and Toyota holds more than 1,300 related patents; China's patents in oxides and composite electrolytes are growing rapidly, and universities and companies are working closely together; American start-ups focus on innovative structural design, such as QuantumScape's "negative electrode" architecture. This patent distribution reflects the differences in technical routes among countries and also foreshadows the possible regional differentiation of the industry in the future. For Chinese companies, building an independent intellectual property system and breaking through the bottleneck of core materials and equipment are the keys to winning this energy storage technology competition.
Solid-state batteries are not only a new product, but also represent a paradigm revolution in energy storage technology. It will fundamentally redefine the safety boundaries, energy limits and application scenarios of batteries. When this technology matures, we may witness the end of electric vehicle range anxiety, the re-imagination of consumer electronics design, and the comprehensive innovation of energy storage methods. Although there are still many challenges to overcome, the commercialization process of solid-state batteries is irreversible. It is moving from the laboratory to the market and from the future to reality.
3. Diversified innovation: sodium ion, lithium metal and other cutting-edge technologies
In the panorama of energy storage technology innovation, multi-route parallel development has become a global consensus. In addition to solid-state batteries, differentiated technical routes such as sodium ion batteries, lithium metal batteries, and flow batteries each have their own advantages, and together constitute a matrix of energy storage solutions that meet different needs. This diversified pattern is both a response to resource constraints and an adaptation to the diversity of application scenarios, reflecting the maturity and rationality of the development of the energy storage industry. Especially under the "dual carbon" goal, no one technology can conquer the world, and complementary synergy is the optimal strategy.
Sodium ion batteries have emerged with their rich resources and cost advantages. Its working principle is similar to that of lithium ion batteries, but sodium replaces lithium as a charge carrier. The crustal abundance of sodium is 423 times that of lithium, and it is evenly distributed, which fundamentally solves the resource bottleneck. In 2024, the material cost of sodium ion batteries will be 30-40% lower than that of lithium iron phosphate, showing strong competitiveness in the field of large-scale energy storage. my country is in a leading position in the world in this field, and companies such as China Science and Technology Sodium and CATL have established a complete industrial chain from materials to batteries. The Guangxi Fulin 10MWh sodium-ion energy storage power station, which was put into operation in May 2024, is the world's first demonstration project of this scale. Its successful operation indicates that the technology is ready for commercialization.
The cathode material system of sodium-ion batteries is mainly divided into three categories: layered oxides, polyanion compounds and Prussian blue analogs. Layered oxides have the best comprehensive performance, with a capacity of up to 130-160mAh/g, and have been the first to achieve industrialization; polyanion compounds have a stable structure and long cycle life, but poor conductivity requires carbon coating modification; Prussian blue analogs are simple to synthesize and low in cost, but the crystal water problem affects performance stability. In terms of negative electrode materials, hard carbon is currently the only commercial option, with a specific capacity of about 300mAh/g, and price is a limiting factor. With the continuous optimization of the material system, the performance of sodium-ion batteries will be further improved. It is expected that the energy density will reach 160-180Wh/kg in 2027, and the cycle life will exceed 5,000 times.
Layered oxides: Na[Ni-Fe-Mn] system has the best comprehensive performance and the fastest industrialization process
Polyanions: Na₃V₂(PO₄)₃ has a stable structure and is suitable for long-life demand scenarios
Prussian blue: low preparation temperature and obvious cost advantage, but the problem of crystal water needs to be solved
Hard carbon anode: Precursor selection is the key, and biomass-based materials have low cost
Lithium metal batteries are another highly concerned ultra-high energy density technology direction. It uses metallic lithium as the anode, with a theoretical capacity of up to 3860mAh/g, which is 10 times that of graphite anode. Combined with solid-state batteries, the energy density of lithium metal batteries is expected to exceed 500Wh/kg, meeting extreme needs such as aviation and military industry. However, the short-circuit risk caused by lithium dendrite growth has always hindered its commercialization. In recent years, the safety of lithium metal batteries has been significantly improved through technologies such as electrolyte modification, three-dimensional current collector design, and artificial SEI membrane. The lithium metal battery demonstrated by SES, a US startup, has achieved an energy density of 400Wh/kg and a cycle life of 500 times, and is expected to be mass-produced on a small scale in 2026.
As a representative technology for long-term energy storage, flow batteries have unique advantages in grid-level applications. All-vanadium liquid flow batteries (VRFB) achieve charging and discharging through changes in the valence state of vanadium ions. The power and capacity can be designed independently, the cycle life exceeds 20,000 times, and the safety is extremely high. Its core components include three parts: the stack, the electrolyte, and the circulation system. The current constraints are mainly high initial cost (about 3,000-4,000 yuan/kWh) and low energy efficiency (70-75%). Through electrolyte formulation optimization (such as mixed acid support electrolyte), stack structure innovation (such as bipolar plate design) and business model innovation (such as electrolyte leasing), the economic efficiency of flow batteries is gradually improving. The 100MW/400MWh all-vanadium liquid flow battery energy storage power station built in Dalian, my country, is the world's largest project and provides an important demonstration for long-term energy storage.
Lithium-sulfur batteries and lithium-air batteries represent more cutting-edge exploration directions. The theoretical energy density of lithium-sulfur batteries is as high as 2600Wh/kg, which is more than 5 times that of lithium-ion batteries, and sulfur resources are abundant and environmentally friendly. However, the "shuttle effect" of polysulfides leads to a short cycle life, and the current best level in the laboratory is about 500 times. This problem is gradually being alleviated by strategies such as building host materials in the positive electrode, developing new electrolytes, and designing multifunctional diaphragms. The theoretical energy density of lithium-air batteries is even more amazing (3500Wh/kg), but it faces challenges such as complex reaction mechanisms and irreversible by-products, and is still in the basic research stage. Although these "post-lithium-ion" technologies are still far from application, they may define the future of energy storage.
Technological innovation is giving birth to new business models. For sodium-ion batteries, the full industrial chain layout of "materials-cells-systems-recycling" has become a common choice for companies; liquid flow batteries have developed innovative models such as electrolyte leasing and capacity sharing; in the field of solid-state batteries, foundry cooperation and patent licensing have begun to emerge. These changes reflect the transformation of the energy storage industry from single product competition to ecosystem competition. Policy support is also advancing with the times. my country's "14th Five-Year Plan for the Development of New Energy Storage" clearly proposes a diversified technology route strategy to avoid the risk of "putting all eggs in one basket".
The diversified development of energy storage technology is not a zero-sum game, but a complementary and progressive relationship. The future market will present a clear stratification pattern: lithium-ion batteries continue to dominate consumer electronics and high-performance electric vehicles; solid-state batteries gradually penetrate the high-end market; sodium-ion batteries will make great strides in the field of large-scale energy storage; liquid flow batteries focus on grid-level long-term energy storage; ultra-high-performance batteries such as lithium metal meet special needs. This multi-technology collaborative ecosystem will be more resilient and adaptable, providing solid support for energy transformation. With the continuous breakthroughs in various routes, the energy storage industry will usher in a new stage of flourishing and promote the high-quality realization of the "dual carbon" goals.
4. Industrialization Challenges and Outlook for the Next Decade
From laboratory breakthroughs to large-scale commercialization, new energy storage technologies face a series of industrialization gaps that must be crossed. These challenges include both scientific and technological issues such as materials and processes, as well as industrial ecological issues such as costs, supply chains, and standards, forming a complex multi-dimensional obstacle system. Analyzing these challenges and planning reasonable leapfrogging paths are crucial to accelerating the commercialization of next-generation battery technology and will determine the competitive position of countries in the future energy landscape.
The industrialization of solid-state batteries faces dual challenges in interface engineering and manufacturing processes. The interface impedance caused by solid-solid contact is one order of magnitude higher than that of liquid-solid contact, which seriously affects the battery power performance. To solve this problem, the industry is exploring a variety of innovative solutions: in-situ formation of a buffer layer to reduce the interface energy barrier, such as the sulfide/oxide composite interface used by Toyota; designing self-healing interface materials to adapt to volume changes during the cycle; and developing three-dimensional electrodes to increase the contact area. In terms of manufacturing, solid-state batteries cannot completely follow traditional lithium battery equipment and require a completely new production process. Sulfide electrolytes need to be produced in a pure argon environment with oxygen concentration controlled below 0.1ppm; oxide electrolytes require high-temperature sintering, high energy consumption and easy brittle fracture. These special requirements have led to a significant increase in equipment investment. Currently, the investment per GWh of production capacity is as high as 800 million to 1 billion yuan, which is 2-3 times that of traditional lithium batteries.
Interface optimization: buffer layer design, surface modification, prestress control and other multi-pronged approaches
Process innovation: dry electrode, room temperature pressing molding, multi-layer stacking and other new process development
Equipment innovation: fully enclosed automated production line, high-precision alignment system, online detection technology
Cost reduction path: simplified material system, improved production yield, and apparent scale effect
Industry chain construction is another key challenge. Solid-state batteries require a new material supply chain. For example, key materials such as LLZO oxide electrolytes and LGPS sulfide electrolytes have not yet formed a large-scale supply; the preparation, processing and transportation of lithium metal negative electrodes require special facilities; new components such as composite current collectors lack standard specifications. This imperfect state of the industrial chain has pushed up material costs. For example, the price of sulfide electrolytes is currently as high as 2,000-3,000 yuan/kg, which is more than 50 times that of liquid electrolytes. To solve this dilemma, leading companies are adopting a vertical integration strategy: Toyota has invested in solid electrolyte raw material companies; CATL has established a joint development mechanism with material suppliers; Qingtao Energy has built its own raw material production line. This "full industry chain collaborative innovation" model is expected to accelerate the industrialization process.
The commercialization barriers of sodium-ion batteries are mainly concentrated in two aspects: performance balance and industrial ecology. Although sodium-ion batteries have advantages in cost and safety, their energy density (120-160Wh/kg) and voltage platform (3.0-3.7V) are low, which limits the application scenarios. Through the innovation of positive and negative electrode materials and the optimization of electrolytes, the performance is steadily improving, and it is expected to reach 180Wh/kg in 2027. The greater challenge lies in establishing an industrial ecology independent of lithium batteries, including supporting systems such as special diaphragms, electrolytes, and current collectors. At present, the sodium-electric industry chain faces the dilemma of "chicken or egg": without scale, it is difficult to reduce costs; with high costs, it is difficult to scale up. The driving role of policy guidance and demonstration projects is crucial. For example, my country's "14th Five-Year Plan for the Development of New Energy Storage" clearly lists sodium-ion batteries as a key development direction, and companies such as the State Grid are also actively promoting demonstration applications.
The lack of standard systems and test evaluation methods also restricts the promotion of new technologies. The safety assessment standards for solid-state batteries are very different from those for traditional lithium batteries. For example, the needle puncture test may no longer be applicable to solid-state batteries; the performance degradation mechanism of sodium-ion batteries is different, and a special life evaluation method needs to be established; there is no unified standard for the system efficiency measurement of flow batteries. These gaps in standards make it difficult to objectively compare product performance and increase the difficulty of market acceptance. Organizations such as the International Electrotechnical Commission (IEC) have started the formulation of relevant standards, but progress is relatively lagging. Chinese companies are actively participating in the international standard competition. For example, CATL has led the formulation of a number of international standards for solid-state batteries, which will help enhance the industry's voice.
In the next decade, energy storage technology will present a tiered development pattern. Before 2025, traditional lithium-ion batteries will still be the absolute main force, and they will continue to reduce costs and increase efficiency through material optimization and process improvement; from 2025 to 2028, semi-solid batteries and sodium-ion batteries will be applied on a large scale, complementing the fields of high-end electric vehicles and large-scale energy storage; from 2028 to 2030, all-solid-state batteries will enter the mass production stage, opening a new era of energy storage technology; after 2030, ultra-high performance technologies such as lithium metal batteries and lithium-sulfur batteries may achieve breakthroughs to meet special needs. This step-by-step evolution is not a simple technology replacement, but a symbiotic and coexisting ecology formed according to the needs of application scenarios.
Policy support is crucial to crossing the bottleneck of industrialization. my country has built a relatively complete policy system: the Ministry of Science and Technology supports cutting-edge technology research through key R&D plans; the Ministry of Industry and Information Technology organizes collaborative innovation projects in the industrial chain; and the Energy Bureau promotes the construction of demonstration application scenarios. This "R&D-industry-market" trinity support model effectively reduces innovation risks. Future policies need to be more precise: strengthen basic research investment in cutting-edge technologies such as solid-state batteries; provide market pull for technologies close to commercialization such as sodium-ion batteries; and improve the price mechanism for long-term energy storage technologies such as flow batteries. Only when the three forces of policy, technology, and market are combined can new technologies accelerate across the "valley of death".
The global competition pattern of the energy storage industry is taking shape. China, Japan, and South Korea are leading in the fields of solid-state batteries and sodium-ion batteries; Europe and the United States focus on ultra-cutting-edge technologies such as lithium metal and lithium air; resource-rich countries such as Australia and Canada focus on raw material supply. This pattern reflects the different industrial bases and strategic choices of various countries. For China, it is necessary to give play to the advantages of market scale and industrial chain, while strengthening basic research to break through original technologies and avoid the risk of "stuck neck". Especially in key links such as solid electrolyte materials and high-precision manufacturing equipment, it is necessary to establish independent and controllable capabilities to be invincible in global competition.
Looking forward to 2030, energy storage technology will usher in a golden age. As various technical routes mature one after another, energy storage costs will continue to decline and application scenarios will continue to expand. Renewable energy + energy storage will become the most economical way to supply electricity; electric vehicle range anxiety will become history; distributed energy systems will be widely popularized. This energy storage revolution will not only change the energy industry, but also reshape the face of multiple industries such as transportation, manufacturing, and information, providing solid support for the sustainable development of human society. In this transformation, China has the opportunity to change from a follower to a leader, contributing Chinese wisdom and solutions to the global energy transformation.
