Chinese battery maker CATL is advancing its solid-state battery development ahead of a planned 2027 pilot program. The company’s recently published patent, PCT/CN2025/086345, focuses on a specialized cathode material and preparation process aimed at improving the stability of sulfide electrolytes. These electrolytes have traditionally suffered from interface contact failures, a challenge that CATL hopes to overcome as it moves from laboratory prototypes toward automotive-grade cells.
CATL’s all-solid-state battery, internally known as Ningde Shidai All-Solid-State, has already achieved a reported energy density of 500 Wh/kg. Development is currently at technology readiness level 4, which involves validation in a lab environment, and the company plans to progress to levels 7 or 8 by the 2027 pilot stage. Level 7 signifies system prototype demonstration in an operational environment, while level 8 refers to actual system completion and qualification for pilot-scale integration into vehicles.
In addition to the patent filing, CATL has secured a key supply chain agreement. In November 2025, it signed a framework agreement with Guangdong Jiayuan Technology to reserve 626,000 tons of copper foil capacity for 2026 through 2028. This allocation, valued at about 66 billion yuan, ensures access to specialized anode current collector materials for both semi-solid and all-solid-state battery routes.
Scaling engineering from 20 Ah lab samples to 60 Ah automotive-grade cells remains a critical hurdle. Sulfide-based solid-state stacks require sustained high compression to maintain consistent interfacial contact. This mechanical approach can necessitate rigid casing designs that somewhat offset the weight advantage provided by high energy density.
Cost also presents a significant barrier. Sulfide solid-state cells are currently three to five times more expensive than conventional lithium-ion options. As a result, CATL anticipates initial applications in areas such as drones and robotics, where high energy density is prioritized over mass-market cost considerations.
Industry estimates suggest all-solid-state battery shipments could reach 13.5 GWh by 2028, compared with 160 GWh for semi-solid systems. With its new patent and supply partnerships, CATL is positioning itself to compete for leadership in the emerging solid-state battery market.
Source: CarNewsChina
