Tuning the surface of LiNi0.8Co0.1Mn0.1O2 primary particle with lithium boron oxide toward stable cycling

Abstract

The interfacial and structural instability of Ni-rich ternary cathode materials impedes its practical application in lithium ion battery with high energy density. Herein, a thin coating layer of lithium borate (~9.5 nm), which is confirmed robustly by the surface characterization techniques including TEM, FE-EPMA, and TOF-SIMS, forms onto the primary particles of LiNi0.8Co0.1Mn0.1O2 via H3BO3 treatment followed by sintering process. During the high-temperature sintering process, the boron dopes into the crystal structure of LiNi0.8Co0.1Mn0.1O2, which increases the interslab of transition metal layer and minimizes the Li+/Ni2+ cation mixing as evidenced by XRD results. Benefited from the stable glassy lithium borate coating and enhanced structural stability, LiNi0.8Co0.1Mn0.1O2 treated with 0.8 mol% H3BO3 delivered much improved cycling stability, especially the high-temperature performance. It achieves a capacity retention of 83.0% (25 °C) and 77.3% (50 °C) after 200 cycles at 200 mA g−1, respectively. This bi-functional modification effects originated from a simple wet coating method with H3BO3 solution may provide a guidance in practical application of Ni-rich cathode materials.