Solid-state batteries, with their revolutionary safety and energy density, are seen as the "ultimate answer" to battery technology.

With the continuous maturity of technology, the industrialization process of solid-state batteries in China is accelerating, and a variety of all-solid-state battery products have recently been intensively unveiled.

The new all-solid-state battery sector has become one of the few bright spots in the market in the near future. Industry insiders believe that in the process of industrialization of all-solid-state batteries, the opportunity with high certainty may lie in the cost reduction of raw material lithium sulfide; Based on the advantages of high safety, high compatibility with existing production lines, simple process and low cost, semi-solid-state batteries are expected to become the transition solution from liquid batteries to all-solid-state batteries, which will precede the mass production of all-solid-state batteries and bring the first round of investment opportunities.

Surpass liquid battery performance across the board

A solid-state battery, as the name suggests, is a type of battery that uses a solid positive and negative electrodes and a solid electrolyte, forming a core difference from traditional lithium batteries that rely on liquid electrolytes. Depending on the liquid electrolyte content, solid-state batteries can be divided into three types: semi-solid (liquid electrolyte mass less than 10%), quasi-solid (liquid electrolyte mass less than 5%), and all-solid state (without any liquid electrolyte).

Compared with liquid batteries, solid-state batteries have three main advantages in terms of performance:

First, the energy density is high. Solid-state batteries have a wide electrochemical window (above 5V), are compatible with more high-voltage cathode materials (high-nickel cathode, nickel-manganese spinel cathode, etc.), and can use silicon and lithium as anode materials, so as to achieve higher energy density. In addition, its high voltage ratio and good safety can also simplify the battery structure and promote the improvement of the energy density of the battery cell. The energy density of ternary iron lithium batteries is usually 180-230Wh/kg, and Penghui Energy (300438. SZ) recently released the first-generation solid-state battery energy density of 280Wh/kg, Weilan New Energy, Guoxuan Hi-Tech (002074. SZ) has developed a semi-solid-state battery with an energy density of 360Wh/kg. The high energy density results in a longer range, and the light-year solid-state battery used in the SAIC Zhiji L6 is reported to have a range of more than 1,000 kilometers.

Second, it is safe. The electrolyte of lithium-ion batteries carries a risk of leakage and is at risk of spontaneous ignition and explosion at high temperatures. The solid-state electrolyte has good thermal stability, non-flammable, non-explosive, no risk of liquid leakage, and because the chemical activity of the solid-state electrolyte is relatively stable, it is less affected by ambient temperature, and has higher stability in the case of collision and extrusion. In addition, the solid-state battery has a wider temperature range, which can better adapt to the high and low temperature environment, and the operating temperature range of Penghui Energy's solid-state battery products is as wide as -20°C~85°C.

Long cycle life. Solid-state batteries use non-flammable solid-state electrolytes instead of flammable organic electrolytes, which can inhibit lithium dendrites from puncturing the separator and cause short circuits, greatly improving battery safety and cycle life. At the same time, the solid-state electrolyte has a high mechanical strength, which can maintain the structural integrity of the battery as it expands or contracts, reducing the degradation of battery performance due to mechanical stress. The interface compatibility between the solid-state electrolyte and the electrode material is better, which reduces the growth of the interfacial impedance, which helps to maintain the long-term stable charge-discharge performance of the battery, and the cycle performance of the solid-state battery can reach about 45,000 times under ideal conditions.

The upgrading of cathode and anode materials brings iterative opportunities

Based on the technical reality that the energy density of liquid batteries is already close to the ceiling, solid-state batteries are expected to partially or even completely replace liquid batteries in the future. So, what are the similarities and differences between the two from the perspective of the industrial chain? What new investment opportunities will emerge from the substitution process?

First of all, look at the "same". From the perspective of battery structure, solid-state batteries are similar to liquid batteries in terms of structure, both of which are composed of positive electrodes, negative electrodes, and electrolytes. From the perspective of the industrial chain, the composition of the two industrial chains is also roughly the same, including the upstream resource end, the midstream manufacturing end and the downstream application end. From a cost perspective, battery materials are the main source of cost.

Looking at "different" again, the main difference between the two is the difference in the materials used. Guolian Securities Research Report pointed out that the development and application of solid-state battery technology will show cascade penetration in the form of "solid-state electrolyte→ new negative electrode→ new cathode", and the core lies in the introduction of new material systems. Among them, the anode material will be upgraded from graphite to silicon-based anode, lithium-containing anode, and lithium metal anode; The cathode materials will be iteratively upgraded from high-nickel ternary to high-voltage high-nickel ternary and ultra-high nickel ternary, and then to new cathode materials such as spinel nickel-manganese oxide and layered lithium-rich base; The diaphragm will be upgraded from a traditional diaphragm to an oxide-coated diaphragm, and eventually the diaphragm will be eliminated.

In terms of cathode, the current lithium iron phosphate and ternary material systems can still be used, and high-voltage cathode materials can be used to achieve higher energy density in the future. At present, the development of solid-state battery cathode is mainly concentrated in high-nickel ternary cathode, lithium nickel manganese oxide, lithium-rich manganese base and other routes. Among them, the high-nickel ternary cathode has become the current mainstream due to its advantages of high energy density, good rate performance and high degree of commercialization. Lithium-rich manganese-based, lithium nickel-manganese oxide and other materials have outstanding advantages in high energy density, which are expected to become a new direction in the future. Among the listed companies, Ronbay Technology (688005. SH), Dangsheng Technology (300073. SZ) have realized the shipment of high-nickel ternary products to solid-state battery companies, Guoxuan Hi-Tech, beiteri (835185. BJ) also has layouts.

In terms of anode, the anode materials of solid-state batteries mainly include graphite, silicon, lithium metal, etc., which are quite different from liquid batteries. In the short and medium term, silicon-based anodes are expected to become the main solution for solid-state battery anode materials. The theoretical specific capacity of silicon is as high as 4200mAh/g, which is more than ten times the gram capacity of the current graphite anode material (372mAh/g), and has the advantages of low potential, high gram capacity, high energy density, sufficient resource reserves and low cost. In the long run, lithium metal will become the ultimate choice for solid-state battery anodes. Lithium metal has the advantages of high theoretical gram capacity and low electrode potential, but there are still some challenges in the industrialization of lithium metal, mainly including the short circuit caused by lithium dendrite puncture separator, the open circuit phenomenon caused by volume change during cycling, and the performance attenuation caused by unstable SEI film.

In terms of silicon-based anode, Shanshan Co., Ltd. (600884. SH), Xiangfenghua (300890. SZ), Putailai (603559. SH), beiteri, Zhongke Electric (300035. SZ) and so on; In terms of lithium metal anode, Ganfeng Lithium (002460. SZ), Tianqi Lithium (002466. SZ) and other traditional giants of lithium resources are expected to enjoy the market dividends brought by negative electrode iteration and demand growth in the long term.

Semi-solid electrolytes increase demand for rare metals

As the primary "variable" in the application of solid-state battery technology, solid-state electrolytes can be mainly divided into polymer solid-state electrolytes and inorganic solid-state electrolytes according to different material types, the former is represented by PEO polyethylene oxide, and the latter includes oxide, sulfide and halide systems.

Among them, oxide electrolytes have good thermal stability and chemical stability to lithium metal, and are usually used in semi-solid-state batteries, and the representative companies of this route include TDK, Toyota, Qingtao Energy, Weilan New Energy, Ganfeng Lithium Battery, Funeng Technology (688567. SH), Guoxuan Hi-Tech, Lishen Battery, Huineng Technology, etc.; Sulfides are considered to be strong candidates for all-solid-state batteries due to their superior conductivity, and the representative companies of this route include Samsung SDI, SK, LG Energy Solution, SolidPower, Panasonic, CATL (300750.HK). SZ), BYD (002594. SZ), Guangzhou Automobile Group (601238. SH), Penghui Energy, etc.

According to the crystal structure of the electrolyte, oxide electrolytes can be divided into perovskite structure type (such as LLTO), garnet structure type (such as LLZO), fast ion conductor type (LATP), thiophosphate (LGPS), etc., which will generate new demand for metal raw materials such as zirconium, lanthanum, titanium, and germanium.

LLZO's raw materials include zirconium dioxide, zirconium nitrate, zirconium carbonate, etc. China's zirconium ore reserves are small, the demand is large, the import dependence is as high as more than 90%, and the supply and demand pattern has been in a tight balance for a long time. Domestic zirconium production enterprises mainly include Oriental Zirconium Industry (002167. SZ), Sanxiang New Materials (603663. SH), Kaisheng Technology (600552. SH) and so on, there are already solid-state battery materials supporting research and development actions.

The raw materials of LLZO/LLTO include lanthanum oxide, lanthanum nitrate, lanthanum hydroxide, etc. China is rich in rare earth resources, contributing 70% of the world's production, and Shenghe Resources (600392. SH), Northern Rare Earth (600111. SH) and other lanthanum oxide production capacity.

The raw materials of LLTO/LATP include titanium dioxide, titanium pyrophosphate, etc. In 2022, the global titanium resource reserves (in terms of TiO2) will be about 700 million tons, mainly ilmenite; China occupies 29% of the world's total, ranking first in the world. The main domestic titanium dioxide manufacturers include China Nuclear Titanium Dioxide (002145. SZ), Longbai Group (002601. SZ), vanadium and titanium shares (000629. SZ) and so on.

Raw materials such as LAGP and sulfide solid electrolyte LGPS include germanium dioxide, germanium sulfide, etc., and the main domestic enterprises are Yunnan germanium industry (002428. SZ), Chihong zinc germanium (600497. SH）。

Lithium sulfide is the key to cost reduction of all-solid-state electrolyte

Sulfide electrolytes are suitable for all-solid-state batteries, and the electrolyte materials mainly include lithium sulfide (Li2S), sodium sulfide (Na2S), potassium sulfide (K2S) and other types, among which the lithium sulfide route has received high attention. The research report of Orient Securities pointed out that in the sulfide electrolyte with different crystal structures, the sulfur-silver-germanium ore electrolyte LPSCl (Li6PS5Cl) is a better technical route choice for sulfide all-solid-state batteries from the perspective of thermal safety characteristics, cost, process maturity and other factors.

However, the high price of lithium sulfide is a major obstacle to the commercialization of sulfide electrolytes. Taking LPSCl as an example, lithium sulfide is a key raw material for the synthesis of LPSCl electrolytes, and the current price of lithium sulfide exceeds US$650,000/ton (about 4.63 million yuan/ton), which is much higher than the commercialization threshold.

At present, the main production methods of lithium sulfide include mechanical ball milling, high-temperature reduction method, solvent method, etc., these preparation processes have high requirements for temperature, moisture and energy consumption, and the preparation process needs to be carried out in an inert atmosphere, resulting in the high price of lithium sulfide, accounting for nearly 80% of the cost of sulfide solid electrolyte. In addition, sulfide solid electrolytes also face problems such as poor solid-solid interface contact, reduced ion transport efficiency, easy reaction with water to produce toxic gases, and inert environment for production and storage. Therefore, improving the preparation process of lithium sulfide has become a key factor in reducing the cost of sulfide electrolyte and even the cost of all-solid-state batteries.

Listed companies that deploy lithium sulfide in advance may be the first to benefit from the development of all-solid-state batteries. At present, Tianqi Lithium has completed the support work related to the industrialization of next-generation lithium sulfide, and has conducted proofing with more than 10 downstream customers, and continued to improve product quality and optimize cost reduction technologies. Engjie shares (002812. At present, Hunan NXT Frontier New Materials, a holding subsidiary of Hunan NXT, has completed the construction and operation of a small-scale annual production capacity of high-purity lithium sulfide products for solid-state use, and has completed the pilot production line of 100-ton lithium sulfide.

In addition, Ronbay Technology applied for a patent related to the preparation method of lithium sulfide in December 2023, which promotes the reaction between the carbon source and lithium sulfate by adding an organic sulfur source, reduces the production of impurities Li2O, and improves the purity of lithium sulfide; Blue Ocean Huateng (300484. SZ), a shareholding subsidiary of Gaoneng Times, has achieved the mass production capacity of tonnage lithium sulfide raw materials under the premise of controllable cost, and the phase XRD test results show that the material purity is high, and the company said that the sulfide electrolyte (LiPSCl) ion conductivity performance test results can benchmark against the world's top level.

　　。

With the continuous maturity of technology, the industrialization process of solid-state batteries in China is accelerating, and a variety of all-solid-state battery products have recently been intensively unveiled.

The new all-solid-state battery sector has become one of the few bright spots in the market in the near future. Industry insiders believe that in the process of industrialization of all-solid-state batteries, the opportunity with high certainty may lie in the cost reduction of raw material lithium sulfide; Based on the advantages of high safety, high compatibility with existing production lines, simple process and low cost, semi-solid-state batteries are expected to become the transition solution from liquid batteries to all-solid-state batteries, which will precede the mass production of all-solid-state batteries and bring the first round of investment opportunities.

Surpass liquid battery performance across the board

A solid-state battery, as the name suggests, is a type of battery that uses a solid positive and negative electrodes and a solid electrolyte, forming a core difference from traditional lithium batteries that rely on liquid electrolytes. Depending on the liquid electrolyte content, solid-state batteries can be divided into three types: semi-solid (liquid electrolyte mass less than 10%), quasi-solid (liquid electrolyte mass less than 5%), and all-solid state (without any liquid electrolyte).

Compared with liquid batteries, solid-state batteries have three main advantages in terms of performance:

First, the energy density is high. Solid-state batteries have a wide electrochemical window (above 5V), are compatible with more high-voltage cathode materials (high-nickel cathode, nickel-manganese spinel cathode, etc.), and can use silicon and lithium as anode materials, so as to achieve higher energy density. In addition, its high voltage ratio and good safety can also simplify the battery structure and promote the improvement of the energy density of the battery cell. The energy density of ternary iron lithium batteries is usually 180-230Wh/kg, and Penghui Energy (300438. SZ) recently released the first-generation solid-state battery energy density of 280Wh/kg, Weilan New Energy, Guoxuan Hi-Tech (002074. SZ) has developed a semi-solid-state battery with an energy density of 360Wh/kg. The high energy density results in a longer range, and the light-year solid-state battery used in the SAIC Zhiji L6 is reported to have a range of more than 1,000 kilometers.

Second, it is safe. The electrolyte of lithium-ion batteries carries a risk of leakage and is at risk of spontaneous ignition and explosion at high temperatures. The solid-state electrolyte has good thermal stability, non-flammable, non-explosive, no risk of liquid leakage, and because the chemical activity of the solid-state electrolyte is relatively stable, it is less affected by ambient temperature, and has higher stability in the case of collision and extrusion. In addition, the solid-state battery has a wider temperature range, which can better adapt to the high and low temperature environment, and the operating temperature range of Penghui Energy's solid-state battery products is as wide as -20°C~85°C.

Long cycle life. Solid-state batteries use non-flammable solid-state electrolytes instead of flammable organic electrolytes, which can inhibit lithium dendrites from puncturing the separator and cause short circuits, greatly improving battery safety and cycle life. At the same time, the solid-state electrolyte has a high mechanical strength, which can maintain the structural integrity of the battery as it expands or contracts, reducing the degradation of battery performance due to mechanical stress. The interface compatibility between the solid-state electrolyte and the electrode material is better, which reduces the growth of the interfacial impedance, which helps to maintain the long-term stable charge-discharge performance of the battery, and the cycle performance of the solid-state battery can reach about 45,000 times under ideal conditions.

The upgrading of cathode and anode materials brings iterative opportunities

Based on the technical reality that the energy density of liquid batteries is already close to the ceiling, solid-state batteries are expected to partially or even completely replace liquid batteries in the future. So, what are the similarities and differences between the two from the perspective of the industrial chain? What new investment opportunities will emerge from the substitution process?

First of all, look at the "same". From the perspective of battery structure, solid-state batteries are similar to liquid batteries in terms of structure, both of which are composed of positive electrodes, negative electrodes, and electrolytes. From the perspective of the industrial chain, the composition of the two industrial chains is also roughly the same, including the upstream resource end, the midstream manufacturing end and the downstream application end. From a cost perspective, battery materials are the main source of cost.

Looking at "different" again, the main difference between the two is the difference in the materials used. Guolian Securities Research Report pointed out that the development and application of solid-state battery technology will show cascade penetration in the form of "solid-state electrolyte→ new negative electrode→ new cathode", and the core lies in the introduction of new material systems. Among them, the anode material will be upgraded from graphite to silicon-based anode, lithium-containing anode, and lithium metal anode; The cathode materials will be iteratively upgraded from high-nickel ternary to high-voltage high-nickel ternary and ultra-high nickel ternary, and then to new cathode materials such as spinel nickel-manganese oxide and layered lithium-rich base; The diaphragm will be upgraded from a traditional diaphragm to an oxide-coated diaphragm, and eventually the diaphragm will be eliminated.

In terms of cathode, the current lithium iron phosphate and ternary material systems can still be used, and high-voltage cathode materials can be used to achieve higher energy density in the future. At present, the development of solid-state battery cathode is mainly concentrated in high-nickel ternary cathode, lithium nickel manganese oxide, lithium-rich manganese base and other routes. Among them, the high-nickel ternary cathode has become the current mainstream due to its advantages of high energy density, good rate performance and high degree of commercialization. Lithium-rich manganese-based, lithium nickel-manganese oxide and other materials have outstanding advantages in high energy density, which are expected to become a new direction in the future. Among the listed companies, Ronbay Technology (688005. SH), Dangsheng Technology (300073. SZ) have realized the shipment of high-nickel ternary products to solid-state battery companies, Guoxuan Hi-Tech, beiteri (835185. BJ) also has layouts.

In terms of anode, the anode materials of solid-state batteries mainly include graphite, silicon, lithium metal, etc., which are quite different from liquid batteries. In the short and medium term, silicon-based anodes are expected to become the main solution for solid-state battery anode materials. The theoretical specific capacity of silicon is as high as 4200mAh/g, which is more than ten times the gram capacity of the current graphite anode material (372mAh/g), and has the advantages of low potential, high gram capacity, high energy density, sufficient resource reserves and low cost. In the long run, lithium metal will become the ultimate choice for solid-state battery anodes. Lithium metal has the advantages of high theoretical gram capacity and low electrode potential, but there are still some challenges in the industrialization of lithium metal, mainly including the short circuit caused by lithium dendrite puncture separator, the open circuit phenomenon caused by volume change during cycling, and the performance attenuation caused by unstable SEI film.

In terms of silicon-based anode, Shanshan Co., Ltd. (600884. SH), Xiangfenghua (300890. SZ), Putailai (603559. SH), beiteri, Zhongke Electric (300035. SZ) and so on; In terms of lithium metal anode, Ganfeng Lithium (002460. SZ), Tianqi Lithium (002466. SZ) and other traditional giants of lithium resources are expected to enjoy the market dividends brought by negative electrode iteration and demand growth in the long term.

Semi-solid electrolytes increase demand for rare metals

As the primary "variable" in the application of solid-state battery technology, solid-state electrolytes can be mainly divided into polymer solid-state electrolytes and inorganic solid-state electrolytes according to different material types, the former is represented by PEO polyethylene oxide, and the latter includes oxide, sulfide and halide systems.

Among them, oxide electrolytes have good thermal stability and chemical stability to lithium metal, and are usually used in semi-solid-state batteries, and the representative companies of this route include TDK, Toyota, Qingtao Energy, Weilan New Energy, Ganfeng Lithium Battery, Funeng Technology (688567. SH), Guoxuan Hi-Tech, Lishen Battery, Huineng Technology, etc.; Sulfides are considered to be strong candidates for all-solid-state batteries due to their superior conductivity, and the representative companies of this route include Samsung SDI, SK, LG Energy Solution, SolidPower, Panasonic, CATL (300750.HK). SZ), BYD (002594. SZ), Guangzhou Automobile Group (601238. SH), Penghui Energy, etc.

According to the crystal structure of the electrolyte, oxide electrolytes can be divided into perovskite structure type (such as LLTO), garnet structure type (such as LLZO), fast ion conductor type (LATP), thiophosphate (LGPS), etc., which will generate new demand for metal raw materials such as zirconium, lanthanum, titanium, and germanium.

LLZO's raw materials include zirconium dioxide, zirconium nitrate, zirconium carbonate, etc. China's zirconium ore reserves are small, the demand is large, the import dependence is as high as more than 90%, and the supply and demand pattern has been in a tight balance for a long time. Domestic zirconium production enterprises mainly include Oriental Zirconium Industry (002167. SZ), Sanxiang New Materials (603663. SH), Kaisheng Technology (600552. SH) and so on, there are already solid-state battery materials supporting research and development actions.

The raw materials of LLZO/LLTO include lanthanum oxide, lanthanum nitrate, lanthanum hydroxide, etc. China is rich in rare earth resources, contributing 70% of the world's production, and Shenghe Resources (600392. SH), Northern Rare Earth (600111. SH) and other lanthanum oxide production capacity.

The raw materials of LLTO/LATP include titanium dioxide, titanium pyrophosphate, etc. In 2022, the global titanium resource reserves (in terms of TiO2) will be about 700 million tons, mainly ilmenite; China occupies 29% of the world's total, ranking first in the world. The main domestic titanium dioxide manufacturers include China Nuclear Titanium Dioxide (002145. SZ), Longbai Group (002601. SZ), vanadium and titanium shares (000629. SZ) and so on.

Raw materials such as LAGP and sulfide solid electrolyte LGPS include germanium dioxide, germanium sulfide, etc., and the main domestic enterprises are Yunnan germanium industry (002428. SZ), Chihong zinc germanium (600497. SH）。

Lithium sulfide is the key to cost reduction of all-solid-state electrolyte

Sulfide electrolytes are suitable for all-solid-state batteries, and the electrolyte materials mainly include lithium sulfide (Li2S), sodium sulfide (Na2S), potassium sulfide (K2S) and other types, among which the lithium sulfide route has received high attention. The research report of Orient Securities pointed out that in the sulfide electrolyte with different crystal structures, the sulfur-silver-germanium ore electrolyte LPSCl (Li6PS5Cl) is a better technical route choice for sulfide all-solid-state batteries from the perspective of thermal safety characteristics, cost, process maturity and other factors.

However, the high price of lithium sulfide is a major obstacle to the commercialization of sulfide electrolytes. Taking LPSCl as an example, lithium sulfide is a key raw material for the synthesis of LPSCl electrolytes, and the current price of lithium sulfide exceeds US$650,000/ton (about 4.63 million yuan/ton), which is much higher than the commercialization threshold.

At present, the main production methods of lithium sulfide include mechanical ball milling, high-temperature reduction method, solvent method, etc., these preparation processes have high requirements for temperature, moisture and energy consumption, and the preparation process needs to be carried out in an inert atmosphere, resulting in the high price of lithium sulfide, accounting for nearly 80% of the cost of sulfide solid electrolyte. In addition, sulfide solid electrolytes also face problems such as poor solid-solid interface contact, reduced ion transport efficiency, easy reaction with water to produce toxic gases, and inert environment for production and storage. Therefore, improving the preparation process of lithium sulfide has become a key factor in reducing the cost of sulfide electrolyte and even the cost of all-solid-state batteries.

Listed companies that deploy lithium sulfide in advance may be the first to benefit from the development of all-solid-state batteries. At present, Tianqi Lithium has completed the support work related to the industrialization of next-generation lithium sulfide, and has conducted proofing with more than 10 downstream customers, and continued to improve product quality and optimize cost reduction technologies. Engjie shares (002812. At present, Hunan NXT Frontier New Materials, a holding subsidiary of Hunan NXT, has completed the construction and operation of a small-scale annual production capacity of high-purity lithium sulfide products for solid-state use, and has completed the pilot production line of 100-ton lithium sulfide.

In addition, Ronbay Technology applied for a patent related to the preparation method of lithium sulfide in December 2023, which promotes the reaction between the carbon source and lithium sulfate by adding an organic sulfur source, reduces the production of impurities Li2O, and improves the purity of lithium sulfide; Blue Ocean Huateng (300484. SZ), a shareholding subsidiary of Gaoneng Times, has achieved the mass production capacity of tonnage lithium sulfide raw materials under the premise of controllable cost, and the phase XRD test results show that the material purity is high, and the company said that the sulfide electrolyte (LiPSCl) ion conductivity performance test results can benchmark against the world's top level.