Sulfide Solid-State Batteries Gaining Traction

The sulfide-based all-solid-state battery (ASSB) route is seeing two major trends in 2025. First, its superior ionic conductivity has made it a consensus choice among researchers and industry players. Second, the commercialization process is accelerating, especially among startups, with clear progress in funding, production capacity, and market expansion.

Firm Lithium Technology Technology: A Three-Pronged Push

Firm Lithium Technology, a Chinese startup, has recently achieved several key milestones across funding, production capacity, and market expansion:

Funding: The company has completed its Series A round, backed by a subsidiary of Chaowei Power and SAIC’s investment arm.

Production Capacity: The company has completed its Series A round, backed by a subsidiary of Chaowei Power and SAIC’s investment arm.

Market Expansion: Firm Lithium has partnered with a Beijing-based premium electric motorcycle brand, marking its expansion beyond consumer electronics. The company aims to achieve vehicle integration by 2026 and scale up to passenger vehicles by 2027.

Early-Stage Competition: Carving Out Niches

Competition among solid-state battery startups is beginning to take shape. For instance, Chunli New Energy, which focuses on polymer-based ASSBs, launched a 200 MWh production line in late 2024, targeting the e-bike market.

Supply Chain Breakthroughs: Electrolyte Production Scaling Up

Upstream players are also making strides:

  • Zhongke Gu’neng: Secured ton-level sulfide electrolyte orders in 2025 and established a 100-ton/year production line alongside a 100 MWh pilot line in Changzhou. The company utilizes proprietary gas-phase synthesis and wet coating technologies.

  • Tianshi Kefeng: Raised tens of millions of RMB in angel funding and plans to build a tens-of-ton electrolyte powder production line in 2025, with expansion to hundred-ton scale between 2026 and 2027. Samples have already been delivered to leading players such as CATL, Gotion, and Ronbay.

  • Idemitsu Kosan : Investing over JPY 21.3 billion (~USD 140 million) to build a lithium sulfide production capacity of 1,000 tons per year by June 2027, supporting Toyota’s ASSB EV launch targets for 2027–2028.

Key Observation: A “Low-to-High” Market Entry Strategy

Most sulfide-based ASSB startups are currently targeting low-speed, light-duty, or cost-insensitive applications. This pragmatic “low-to-high” strategy allows them to secure early market share and validate their technologies on smaller cells before moving into passenger EV applications.

Notably, no sulfide-focused startup has yet established a deep partnership with an automaker in China. In contrast, companies pursuing oxide-polymer composite routes—such as Tailan, Weilan, and Qingtao—have already secured strong backing from EV manufacturers through a stepwise “semi-solid to all-solid” transition strategy.

Whether sulfide-focused startups can bridge this gap and establish a leading position remains a key development to watch.

 

Note: This article is adapted and summarized from publicly available reporting by Gaogong Lithium Battery (GGII). The original data and viewpoints belong to GGII.

 

 

 

 

/by