Solid-state batteries have emerged as a key focus for developers with rising investment since the beginning of the year.

Battery sector information provider Gaogong Industry Institute said new production capacity for solid-state batteries surpassed 142 gigawatt-hours from January to July, with total investment exceeding 64.4 billion yuan ($9 billion).

A solid-state battery employs a solid electrolyte for ionic conduction between its electrodes, in contrast to the liquid or gel polymer electrolytes used in traditional batteries.

Experts said solid-state batteries offer key advantages over current mainstream liquid batteries, including higher safety and greater energy density, which align with the increasing requirements for safety and mileage from electric vehicle users.

Several leading domestic battery manufacturers have already announced their plans for solid-state battery production.

CATL said recently that it is increasing investment in solid-state batteries, aiming to achieve small-scale production by 2027. Sunwoda said in June that its solid-state battery division — which has been in development since 2015 — is working on the first generation of 400 watt-hours per kilogram and the second generation of 500Wh/kg solid-state batteries.

In May, Gotion High-Tech unveiled its new battery, which uses solid-state battery tech to achieve a cell energy density of 350Wh/kg — over 40 percent higher than traditional liquid ternary lithium batteries. Other domestic firms like CALB Group and EVE Energy have also announced plans for solid-state battery products.

Experts said that large-scale mass production of solid-state batteries remains out of reach in the short term due to various technical limitations. High costs also pose a significant hurdle to the large-scale industrialization of solid-state batteries.

According to a research report from the CITIC Securities, currently, the total cost of oxide and sulfide semisolid batteries is approximately 0.76 yuan/Wh and 0.86 yuan/Wh, respectively — significantly higher than that of liquid lithium-ion batteries. Future cost reductions will require further research investment and scaled production.

As more players enter the solid-state battery market, competition will drive tech advances and manufacturing process optimization, accelerating commercialization, experts said.

Notably, a workstation of Ouyang Minggao, an academician at the Chinese Academy of Sciences, made significant progress in developing sulfide electrolytes — a key material in solid-state batteries.

The nano-scale sulfide electrolyte developed in the workstation is nearing mass production, with a pilot production line with an annual capacity of hundreds of metric tons expected to begin construction by the end of this year. If successful, a 1,000-ton production line will be established before 2026.

Ouyang said the industrialization of solid-state batteries still faces a series of scientific challenges that need to be addressed at various levels including key materials and composite electrodes.

Chen Jun, an academician at the CAS, said that the industrialization of solid-state batteries would revolutionize the EV industry and open up new markets such as electric aviation, which will be a globally significant technological breakthrough.

Chen's team has developed a new solid-state battery sample with an energy density of 400Wh/kg, surpassing the 300Wh/kg lithium-ion batteries currently on the market by 30 percent.

"In the next one to two years, we aim to make breakthroughs in the research and development of the 600Wh/kg solid-state battery, enabling EVs to travel over 1,000 kilometers on a single charge," Chen said.

"Although there are currently solid-state battery samples, industrialization of solid-state batteries remains challenging due to high costs. There are many other challenges related to the stability of solid electrolytes, interfacial reactions and system integration," he added.