硼酸喷雾包覆改性镍钴铝酸锂的制备及其电化学性能研究

针对镍钴铝酸锂（NCA）三元正极材料普遍存在的循环寿命差、浆料容易凝胶等缺点进行了硼酸喷雾包覆的改性。采用X 射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）及电化学测试等方法对硼酸包覆改性前后的材料性能进行了对比表征和分析。结果表明：喷雾包覆后可以在NCA正极材料表面形成一层保护层,改性后的NCA三元正极材料循环寿命有明显提升,特别是高温（45 ℃）1C/1C倍率下循环50次容量保持率由改性前的88.0%提升至改性后的95.2%,提升近7%;硼酸包覆可以改善NCA表面特性,使正极浆料稳定性大大提高。改性后的NCA正极浆料可以稳定放置168 h（7 d）,解决了NCA正极材料容易凝胶的问题。

Study on preparation and electrochemical properties of lithium nickel cobalt aluminate modified by boric acid spray coating

Boric acid spray coating was used to modify lithium nickel-cobalt aluminate（NCA） ternary cathode materials for their poor cycle life and poor slurry stability.The properties of boric acid coated materials were characterized and analyzed by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and electrochemical tests.The results showed that a protective layer could be formed on the surface of NCA cathode material after spray coating,and the cycle life of NCA ternary-element cathode material after modification was significantly improved,especially the capa-city retention rate of 1C/1C 50 cycles at high temperature（45 ℃） was increased from 88.0% to 95.2% after modification,in-creasing by nearly 7 percentage points.Boric acid coating could improve the surface characteristics of NCA and greatly impro-ved the stability of positive electrode paste.The modified NCA positive electrode paste could be stably placed for 168 h （7 d）,which solved the problem that NCA positive electrode material was easy to gel.