The world's leading electric vehicle manufacturer BYD has officially protected a patent for a new cathode structure designed for cutting-edge solid-state batteries. The engineering solution relies on a combination of halide and sulfide electrolytes, with its main goal being to ensure durable and stable contact between the solid components in the cell during continuous charging and discharging cycles. The current documentation shows the company's clear research direction, but at this stage does not mean that the technology is fully ready for mass production.
The patent application under registration number CN202510126712.6 was officially published by the State Intellectual Property Administration of China on July 28, 2026 under number CN122474592A. The content describes in detail the chemical composition and the production method for making the composite cathode. However, the submitted documents explicitly lack data on tests of finished battery blocks, tests in real cars or specific timeframes for the market debut.
BYD's innovative architecture combines two separate types of solid electrolyte with the active material of the cathode. The halogen component is made of a finer microstructure with smaller particles, while the sulfide electrolyte relies on significantly larger particles. Their joint functioning in the composite electrode allows the materials to complement each other, which achieves a far more reliable connection within the cathode structure itself.
This development is of critical importance for the concept of solid-state cells, where the liquid electrolyte is completely replaced by solids. During the constant operation of the battery, the individual elements expand and contract their volume, which inevitably leads to loosening of the mechanical contact and a sharp increase in internal resistance. The new engineering solution should significantly mitigate this negative effect, although the patent text has not yet provided factory laboratory results to confirm the efficiency in serial cells.
The chief scientist of BYD Group, Liang Yubo, previously identified the instability of the contact between solid surfaces as one of the most serious barriers to the industrial production of this type of battery. According to him, the technology is still in an important phase of overcoming basic technical challenges.
This is far from a unique case in the development activities of the Chinese giant. In May 2026, BYD patented a composite membrane combining inorganic solid electrolyte particles with a network of polymer fibers. The company has filed applications for other composite cathode variants, as well as for a two-layer coating of the electrodes.
At the same time, BYD’s battery technology director, Sun Huajun, hinted that the active cathode material content in their solid-state cells has already exceeded 85%. However, the specific test conditions and parameters surrounding the achievement remain confidential. Ultimately, the new patent should be seen as an important milestone in the company’s ongoing research and development activities, rather than an application for immediate mass production.