Controlling Surface Structure and Primary Particle Size to Enhance Performance and Reduce Gas Evolution in Lithium- and Manganese-Rich Layered Oxide Cathodes.

ABSTRACT

Practical application of lithium- and manganese-rich layered oxide cathodes has been hindered despite their high performance and low cost owing to high gas evolution accompanying capacity loss even in a conservative voltage window. Here, we control the surface structure and primary particle size of lithium- and manganese-rich layered oxide cathodes not only to enhance the electrochemical performance but also to reduce gas evolution. Sulfur-coated Fm3̅m/R3̅m double reduced surface layers and Mo doping dramatically reduce gas evolution, which entails the improvement of electrochemical performance. With the optimization, we prove that it is competitive enough to conventional high-nickel cathodes in the aspects of gas evolution as well as electrochemical performance in the conservative voltage window of 2.5-4.4 V. Our findings provide invaluable insights on the improvement of electrochemical performance and gas evolution properties in lithium- and manganese-rich layered oxide cathodes.