China’s leading battery manufacturer, CATL, is making significant strides in solid-state battery technology, with a focus on overcoming the instability issues inherent in sulfide-based electrolytes. The company has initiated pilot development of a high-energy-density (500 Wh/kg) solid-state battery, branded domestically as Ningde Shidai All-Solid-State, and is working towards small-scale production by 2027. This push coincides with China’s plans to introduce its first national technical standard for solid-state batteries in July 2026, signaling the country’s intent to lead in this emerging technology.
Addressing Sulfide Instability Through Patent Filing
A recently published patent (PCT/CN2025/086345) highlights CATL’s efforts to stabilize sulfide electrolytes, a long-standing challenge in solid-state battery development. The patent details a specific positive electrode active material and preparation method designed to mitigate interface contact failures, a key problem with sulfide electrolytes. Currently at technology maturity level 4, CATL aims to reach levels 7 or 8 by 2027 – a stage where cells are ready for automotive integration.
Why this matters: Sulfide electrolytes offer higher conductivity than solid polymers, but their instability at the interface creates performance degradation. CATL’s patent signals a focused effort to resolve this critical issue, potentially unlocking high-performance solid-state batteries.
Supply Chain Security: Copper Foil Deal Confirmed
CATL has secured a substantial supply of copper foil through a Cooperation Framework Agreement with Guangdong Jiayuan Technology. This deal reserves 626,000 tons of copper foil capacity for the period 2026-2028, valued at approximately $9.6 billion USD. The move secures specialized anode current collector materials for both semi-solid and all-solid-state battery production.
Context: This massive capacity reservation demonstrates CATL’s commitment to industrial-scale production. While Jiayuan’s current output is small, the long-term investment indicates a strategic pivot towards mass manufacturing, ensuring they won’t be constrained by material shortages.
The 60Ah Engineering Hurdle
CATL’s primary engineering challenge lies in scaling from 20Ah prototype cells to 60Ah automotive-grade cells. Sulfide solid-state stacks require constant high-tonnage compression to maintain interfacial contact, making manufacturing more complex than traditional liquid electrolyte batteries. The rigid casing designs needed to maintain this compression can offset the weight advantages of high energy density.
Why it’s difficult: Unlike liquid-electrolyte cells, solid-state batteries demand extreme precision in assembly and compression. This mechanical brutality makes scaling to automotive grade a significant engineering feat.
Realistic Expectations and Deployment Strategy
Despite progress, CATL acknowledges that engineering hurdles and cost remain major barriers. Solid-state cells are currently 3–5 times more expensive than conventional lithium-ion. The company has dismissed rumors of 2,000 km-range EVs by 2027, instead focusing initial deployments in applications where energy density is paramount, such as drones and robotics.
The bigger picture: This pragmatic approach suggests CATL is prioritizing technological maturity over immediate mass-market adoption. Early deployments in niche markets will allow them to refine manufacturing processes and reduce costs before targeting the automotive sector.
Global Competition and Market Outlook
CATL remains a leading applicant in solid-state battery patents, competing with global players like Toyota and Samsung. By 2028, all-solid-state shipments are projected to reach 13.5 GWh, but will still be dwarfed by the 160 GWh of semi-solid shipments.
Conclusion: CATL is betting heavily on mastering solid-state technology, particularly scaling to the 60Ah automotive standard. Securing intellectual property and material supply chains are key to their strategy, but the race to industrialization is far from over. The company’s success hinges on overcoming engineering challenges and cost reduction, positioning them to potentially dominate the next generation of battery technology.
