锂离子电池镍基正极材料水溶液体系中氧化铝包覆研究

Al_2O_3 coated Ni-rich cathode materials in aqueous solution system for lithium ion batteries

在水溶液体系中,采用沉淀法制备了Al_2O_3包覆的Li Ni_(0.9)Co_(0.1)O_2镍基正极材料。当Al_2O_3包覆量(质量分数)为0.5%时,Al不能完全被沉淀;当Al_2O_3包覆量(质量分数)为2.0%时,Al_2O_3不能完全被沉淀在Li Ni_(0.9)Co_(0.1)O_2表面。通过XRD、SEM、电池测试仪对样品的结构、形貌和电化学性能进行了表征。结果表明,当Al_2O_3包覆量(质量分数)为1.0%和1.5%时,样品球形表面的洁净程度变差,结构仍保持良好的层状结构,但能降低阳离子混排程度;在0.2C、2.75~4.25 V测试条件下,Al_2O_3包覆量(质量分数)为1.0%和1.5%的样品,首次放电容量和库伦效率下降,循环性能提高;50次循环后,1.0%Al_2O_3包覆量的样品放电容量保持率最高,且放电容量大于未包覆的产物。

In aqueous solution system,Al2O3 coated Ni-rich cathode material was synthesized by precipitation method.When the coating amount（mass fraction）of Al2O3 is 0.5%,Al can not be completely precipitated.When the coating amount（massfraction）of Al2O3 is 2%,Al2O3can not be completely precipitated on the surface of Li Ni（0.9）Co（0.1）O2.The structure,morphology and electrochemical properties were characterized by XRD,SEMand battery tester.The resultes indicate that,when the coating amount（mass fraction）of Al2O3is 1.0%or 1.5%,the cleanliness of the spherical surface of the sample get worse,and the sample maintains a good layered structure,but the degree of cationic mixing reduces.Under the test conditions of 2.75-4.30 V and 0.2C,when the coating amount（mass fraction）of Al2O3is 1.0% or 1.5%,the first discharge capacity and coulomb efficiency are reduced,but its cyclic performance is improved.After 50 cycles,the 1.0% Al2O3 coated sample has the highest retention rate of discharge capacity,and its discharge capacity is larger than that of uncoated Li Ni（0.9）Co（0.1）O2.