Enhanced electrochemical performance of LiNi0.8Co0.1Mn0.1O2 with 3D-SiO2 framework by a new negative pressure immersion method

LiNi0.8Co0.1Mn0.1O2 is one of the most promising lithium ion batteries cathode materials; however, during charge/discharge process, it suffers from capacity fading considering intergranular cracking. Herein we develop an original concept to alleviate this problem by negative pressure immersion treatment. 3D-SiO2 framework is formed in the intergranular voids and grain boundaries (functioning as the buffer zone and transfer-bridge) as well as the SiO2 protective layer is completely and homogeneously coated on the surface of the pristine particles through hydrolytic condensation reaction of tetraethoxysilane (TEOS). The 3D-SiO2 framework has two advantages: firstly, acting as a buffer zone, the framework can effectively inhibit the generation and extension of intergranular cracking; secondly, the same as SiO2 protective layer on the surface of the particles, the 3D-SiO2 framework can impede the side reaction between primary particles (grains) and electrolyte inside particles. As a results, the as-modified LiNi0.8Co0.1Mn0.1O2 exhibits enhanced cycling performance with 92.4% capacity retention after 100 cycles at 1 C (200 mAh·g-1), while that of the pristine particles and normal coating treatment particles is only 55.4% and 82.6% respectively. Moreover, the thermal stability (60 °C) enhances distinctly and the rate performance is significantly improved at high rate (2, 3 and 5 C).