Li-Rich Layered Oxide Microspheres Prepared by the Biomineralization as High-Rate and Cycling-Stable Cathode for Li-Ion Batteries

Biomineralization is a green and skillful approach to prepare Li-rich layered oxides with hierarchical micro/nano structure as high-performance cathode for lithium-ion batteries. In this work, to enhance the high-rate capability and cycle stability, Li-rich layered oxide Li1.17Ni0.14Co0.13Mn0.56O2 microspheres are synthesized through a simple biomineralization function, in which yeast cells are used as the nucleating agent and structural template without using any organic complexing agents. These microspheres are constructed by densely aggregated primary nanocrystallites (30-100 nm in size) with abundant mesopores. Furthermore, the in situ surface modification can be induced by the few-layered black phosphorus with good conductivity of electrons, which are derived from the biomass adhering on the primary nanocrystalline structures. Such hierarchical micro/nano assembly structure of the active materials provides more electrochemical reactive sites, facilitates rapid Li-ion diffusion, and suppresses undesirable side reactions caused by the electrolyte corrosion. The Li-rich layered oxide presents good electrochemical performance, including reversible capacity and cycle stability. The large discharge capacity of 318.7 mAh g(-1) is obtained for Li-rich layered oxide at 0.1 degrees C rate. At higher rate of 10 degrees C, the large capacity of 134.5 mA h g(-1) is maintained. After 270 cycles at varied charge/discharge rates, the high capacity retention of 97.2% is achieved.