Researchers discover general design principles for lithium battery cathode materials.

Title context: Text: The performance of lithium-ion batteries depends to a large extent on their cathode materials. In traditional R&D, researchers add about 1% of specific trace elements to cathode materials to explore ways to improve lithium-ion transport efficiency and structural stability. However, faced with the many options in the periodic table, R&D has relied mostly on "empirical trial and error," like a "hodgepodge," lacking clear design basis and followable screening rules. On October 1, a team from the Shenyang National Laboratory for Materials Science at the Institute of Metal Research, Chinese Academy of Sciences, published research results in Nature Synthesis, proposing a trace-element screening strategy based on physicochemical mechanisms, advancing cathode material design from "empirical trial and error" toward "goal orientation." To address the two problems of "lithium ions moving slowly" and "material structure being unable to remain stable," the research team started from underlying physicochemical mechanisms and proposed a more targeted element screening method: first, selecting elements with lower ionic charge density, which can reduce the obstruction encountered by lithium-ion migration and make it easier for lithium ions to move quickly within the material; second, selecting elements that bind more firmly with oxygen, which can enhance the stability of the crystal framework and make the material less prone to structural damage during repeated charge and discharge. Based on this strategy, the team synergistically introduced four elementsmagnesium, calcium, titanium, and zirconiumto prepare a multi-element trace-doped cobalt-free high-nickel cathode material. Electrochemical tests showed that the material combines excellent fast charge-discharge, long-cycle, and low-temperature performance: with only 3 minutes of ultrafast charging, the charge can reach nearly 80%; under 6-minute fast charge-discharge conditions, after 350 cycles, the capacity retention rate still reached 82.4%. A 5.74Ah battery made with this material still achieved an energy density of 278.6Wh/kg at minus 20 degrees Celsius, providing a new option for the application of new energy vehicles and energy storage equipment in cold regions. This research established followable design rules for the selection of multiple trace elements, transforming material R&D from relying on experience to "try" into "selecting with goals," and providing new ideas for the precise design of high-performance lithium-ion battery cathode materials as well as other functional materials.