高镍三元正极材料 LiNixCoyMn1−x−yO2(NCM, ω(Ni)>60%)由于粉体颗粒表面的 相变, 电解液副产物 HF 的侵蚀, 过渡金属离子的溶解等问题, 其循环性能及安全稳定性一直 不理想. 通过原子层沉积 (atomic layer deposition, ALD) 反应在高镍 LiNi0.8Co0.1Mn0.1O2 (NCM811) 正极材料表面均匀沉积了超薄 TiO2 涂层, 用于改善其电化学性能. 研究结果表 明: 通过 ALD 反应沉积 TiO2 后, 改性 NCM811 的性能明显改善; 超薄 TiO2 涂层阻碍了 NCM811 活性颗粒与电解液的直接接触, 提高了材料的循环稳定性; 在循环过程中, 超薄涂层 不会影响锂离子的传输. 通过 ALD 反应沉积超薄涂层为改性电极材料提供了新思路.

The nickel-rich cathode, LiNixCoyMn1−x−yO2 (NCM, ω(Ni)>60%), suffers from phase transitions on the surface of particles during cycling that cause the electrolyte by-product HF to corrode the material and cause the dissolution of transition metal ions. These problems seriously affect the application of NCMs. In this study, atomic layer deposition (ALD) was used to uniformly deposit a TiO2 coating on the surface of a LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material to improve its electrochemical performance. The results demonstrated a significant improvement in the performance of NCM811 after ALD of TiO2. The ultra-thin TiO2 coating hindered direct contact between the NCM811 active particles and the electrolyte, which improved the cycle stability of the NCM811. The ultra-thin coating did not affect the transmission of lithium ion during cycling. This method for ALD opens a new avenue for the surface modification of electrode materials.