BYD has published a new patent application outlining an advanced cathode composite structure for solid-state batteries, offering fresh insight into the company’s ongoing research into next-generation battery technologies. While the filing highlights a novel material design aimed at improving battery performance, it does not indicate that the technology is ready for commercial production or deployment in electric vehicles.
The patent application (CN202510126712.6), published by the China National Intellectual Property Administration (CNIPA) on July 28, 2026, describes a cathode composite material and its preparation method for all-solid-state battery applications. The disclosure was first reported by Sina.
According to the patent, BYD’s design combines two different solid electrolyte particle systems within the cathode structure. It uses smaller-particle halide electrolytes alongside larger-particle sulfide electrolytes, which are integrated with the cathode active material to create a composite electrode. The approach is intended to improve the interface between battery materials, one of the most significant engineering challenges in all-solid-state battery development.
Maintaining stable contact between solid components during repeated charging and discharging cycles remains a key obstacle to improving the durability and performance of solid-state batteries. The dual-electrolyte design aims to address this issue by optimising the interaction between the cathode and electrolyte materials.
BYD Group Chief Scientist Lian Yubo has previously identified solid-solid interface stability as one of the biggest technical barriers to the industrialisation of solid-state batteries, describing the technology as still being in the “tackling stage.” The newly published patent provides further details on BYD’s material research but does not include production validation data or confirm testing in electric vehicles.
The latest patent adds to BYD’s growing portfolio of intellectual property related to solid-state battery technology. Earlier this year, the company disclosed another patent covering a composite solid electrolyte membrane that combines inorganic solid electrolyte particles with a polymer electrolyte fibre network. That filing also focused on sulfide-based electrolyte materials for next-generation batteries.
BYD has previously filed several patents related to cathode structures, including CN113725405A, which covers a cathode composite structure, and CN121237834A, which details a dual-layer cathode coating design. Together, these filings indicate the company’s continued investment in material innovations that could improve the performance, safety and energy density of future solid-state batteries.
The company has also shared limited technical updates on its research. BYD Lithium Battery CTO Sun Huajun previously stated that the proportion of cathode active material in the company’s all-solid-state battery architecture had exceeded 85%, although no detailed performance data or testing conditions have been disclosed.
Industry experts caution that patent filings primarily reflect a company’s research direction rather than the commercial readiness of a technology. Many innovations disclosed through patents may require years of further development, validation and manufacturing optimisation before reaching mass production.
The broader battery industry continues to invest heavily in solid-state battery research as manufacturers seek higher energy density, improved safety and faster charging capabilities. However, scaling laboratory breakthroughs into commercially viable products remains a significant challenge.
CATL Chairman Robin Zeng has also stated that large-scale commercial adoption of solid-state batteries is still several years away, citing unresolved manufacturing complexities and technical hurdles.
Meanwhile, research led by Wu Fan at the Institute of Physics, Chinese Academy of Sciences, found that smaller sulfide electrolyte particles improved capacity retention by nearly 18 percentage points under laboratory conditions compared with larger particles. Although the findings provide valuable industry context, they are not directly related to BYD’s battery programme.
BYD’s latest CNIPA patent publication offers another glimpse into the BYD solid-state battery research strategy. While the dual-electrolyte cathode design demonstrates continued progress in material engineering, the company has not disclosed whether the technology will be incorporated into future production battery cells or electric vehicles.
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