LiNi0.8Co0.15Al0.05O2（NCA）正极材料的磷酸表面改性

Surface modification of LiNi0.8Co0.15Al0.05O2（NCA） cathode material using phosphoric acid

针对新一代空间型号产品对储能电源提出的更高需求,提出采用表面改性的方法提升LiNi0.8Co0.15Al0.05O2(NCA)正极材料在锂离子电池中的循环稳定性。通过采用磷酸(H3PO4)对NCA正极材料进行表面处理,H3PO4会与NCA颗粒表面的含锂碱性物质发生反应,从而在NCA颗粒表面生成稳定且导电性良好的Li3PO4界面层。循环以及阻抗测试结果表明,经H3PO4表面处理的NCA材料组装电池循环50次后电池容量为170.5 mA·h/g,容量保持率达到94%以上,界面阻抗得到抑制。H3PO4表面处理有效抑制了NCA颗粒表面碱性残留对电化学性能的不良影响,提升了界面稳定性,获得了更好的循环性能。

The next generation of space products put forward higher demand for energy storage system, and the surface modification method is proposed to improve the cyclic stability of LiNi0.8Co0.15Al0.05O2(NCA) cathode material in lithium ion batteries. By using phosphoric acid(H3PO4) to treat the NCA cathode materials, H3PO4 reacts with the lithium-containing alkaline substances on the surface of NCA, so as to generate a stable and conductive Li3PO4 interface layer on the surface of NCA particles. As a result, the H3PO4-modified NCA shows better capacity retention(170.5 mA·h/g,94%) and lower impedance after 50 cycles than the bare one, which is attributed to the presence of the Li3PO4-based coating layer. H3PO4 surface modification method has positive effects on the electrochemical performance and structural integrity of the NCA electrode materials.