Laskar Masihhur R, Jackson David H K, Guan Yingxin, Xu Shenzhen, Fang Shuyu, Dreibelbis Mark, Mahanthappa Mahesh K, Morgan Dane, Hamers Robert J, Kuech Thomas F
Department of Chemical and Biological Engineering, University of Wisconsin Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States.
Department of Material Science and Engineering, University of Wisconsin Madison , 1509 University Avenue, Madison, Wisconsin 53706, United States.
ACS Appl Mater Interfaces. 2016 Apr 27;8(16):10572-80. doi: 10.1021/acsami.5b11878. Epub 2016 Apr 13.
Metal oxide coatings can improve the electrochemical stability of cathodes and hence, their cycle-life in rechargeable batteries. However, such coatings often impose an additional electrical and ionic transport resistance to cathode surfaces leading to poor charge-discharge capacity at high C-rates. Here, a mixed oxide (Al2O3)1-x(Ga2O3)x alloy coating, prepared via atomic layer deposition (ALD), on Li[Ni0.5Mn0.3Co0.2]O2 (NMC) cathodes is developed that has increased electron conductivity and demonstrated an improved rate performance in comparison to uncoated NMC. A "co-pulsing" ALD technique was used which allows intimate and controlled ternary mixing of deposited film to obtain nanometer-thick mixed oxide coatings. Co-pulsing allows for independent control over film composition and thickness in contrast to separate sequential pulsing of the metal sources. (Al2O3)1-x(Ga2O3)x alloy coatings were demonstrated to improve the cycle life of the battery. Cycle tests show that increasing Al-content in alloy coatings increases capacity retention; whereas a mixture of compositions near (Al2O3)0.5(Ga2O3)0.5 was found to produce the optimal rate performance.
金属氧化物涂层可以提高阴极的电化学稳定性，从而延长其在可充电电池中的循环寿命。然而，此类涂层通常会给阴极表面带来额外的电子和离子传输阻力，导致在高倍率下充放电容量不佳。在此，通过原子层沉积（ALD）在Li[Ni0.5Mn0.3Co0.2]O2（NMC）阴极上制备了一种混合氧化物(Al2O3)1-x(Ga2O3)x合金涂层，该涂层提高了电子导电性，并且与未涂层的NMC相比，倍率性能得到了改善。采用了一种“共脉冲”ALD技术，该技术能够使沉积膜实现紧密且可控的三元混合，以获得纳米厚的混合氧化物涂层。与金属源的单独顺序脉冲相比，共脉冲允许对膜的组成和厚度进行独立控制。已证明(Al2O3)1-x(Ga2O3)x合金涂层可提高电池的循环寿命。循环测试表明，合金涂层中Al含量的增加会提高容量保持率；而发现接近(Al2O3)0.5(Ga2O3)0.5的组合物混合物可产生最佳倍率性能。
