Enhanced microstructure stability of LiNi0.8Co0.1Mn0.1O2 cathode with negative thermal expansion shell for long-life battery

With high specific energy density, Ni-rich layered LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) material has become one promising cathode candidate for advanced lithium-ion batteries (LIBs). However, severe capacity fading induced by microstructure degradation and deteriorated interfacial Li + transportation upon repeated cycling makes the commercial application of NCM cathode in dilemma. To address these issues, LiAlSiO 4 (LASO), one unique negative thermal expansion (NTE) composite with high ionic conductivity, is utilized as a coating layer to improve the electrochemical performances of NCM material. Various characterizations demonstrate that LASO modification can endow NCM cathode with significantly enhanced long-term cyclability, through reinforcing the reversibility of phase transition and restraining lattice expansion, as well as depressing microcrack generation during repeated delithiation-lithiation processes. The electrochemical results indicate that LASO-modified NCM cathode can deliver an excellent rate capability of 136 mAh g −1 at a high current rate of 10 C (1800 mA g −1 ), larger than that of the pristine cathode (118 mAh g −1 ), especially higher capacity retention of 85.4% concerning the pristine NCM cathode (65.7%) over 500 cycles under 0.2 C. This work provides a feasible strategy to ameliorate the interfacial Li + diffusion and suppress the microstructure degradation of NCM material during long-term cycling, which can effectively promote the practical application of Ni-rich cathode in high-performance LIBs.