Kim Young-Jin, Rajagopal Rajesh, Kang Sung, Ryu Kwang-Sun
Department of Chemistry, University of Ulsan, Doowang-dong, Nam-gu, Ulsan 44776, Republic of Korea.
Research Institute of Industrial Science & Technology, San Hyoja-dong, Pohang 790-330, Republic of Korea.
ACS Omega. 2021 Mar 8;6(10):6824-6835. doi: 10.1021/acsomega.0c05942. eCollection 2021 Mar 16.
NiCoS nanoparticles (NPs) were dry coated on LiNiCoMnO (NCM622) cathode using a resonant acoustic coating technique to produce all-solid-state lithium batteries. The NiCoS coating improved the electrochemical properties of the NCM622 cathode. In addition, NiCoS eliminated the space-charge layer and the cathode showed an excellent affinity with the interface with a sulfide-based solid electrolyte as an inert material. X-ray diffraction patterns of NCM622 coated with NiCoS showed the same peak separations and lattice parameters as those of bare NCM622. Field-emission scanning electron microscopy and electron dispersive spectroscopy mapping analyses showed that 0.3 wt% NiCoS-coated NCM622 had an evenly modified surface with NiCoS NPs. X-ray photoelectron spectroscopy (XPS) revealed that the surface of 0.3 wt% NiCoS-coated NCM622 had two different S 2p peaks, a Co-S peak, and Ni and Co peaks, compared to those of bare NCM622. Electrochemical studies with electrochemical impedance spectroscopy and galvanostatic charge-discharge cycle performances showed that NiCoS-coated NCM622 retained a higher specific capacity over multiple cycles than bare NCM622. Especially, 0.3 wt% NiCoS-coated NCM622 exhibited a capacity retention of 60.6% at a current density of 15 mA/g for 20 cycles, compared to only 37.3% for bare NCM622. Finally, interfacial XPS and transmission electron microscopy-electron energy loss spectroscopy analyses confirmed the stable state of 0.3 wt% NiCoS-coated NCM622 with minimal side reactions.
采用共振声学涂层技术将硫化镍钴纳米颗粒（NPs）干涂覆在锂镍钴锰氧化物（NCM622）阴极上，以制备全固态锂电池。硫化镍钴涂层改善了NCM622阴极的电化学性能。此外，硫化镍钴消除了空间电荷层，并且该阴极与作为惰性材料的硫化物基固体电解质的界面表现出优异的亲和力。涂覆有硫化镍钴的NCM622的X射线衍射图谱显示出与裸NCM622相同的峰间距和晶格参数。场发射扫描电子显微镜和电子色散光谱映射分析表明，0.3 wt%硫化镍钴涂覆的NCM622表面被硫化镍钴纳米颗粒均匀改性。X射线光电子能谱（XPS）显示，与裸NCM622相比，0.3 wt%硫化镍钴涂覆的NCM622表面有两个不同的S 2p峰、一个Co-S峰以及Ni和Co峰。通过电化学阻抗谱和恒电流充放电循环性能进行的电化学研究表明，涂覆有硫化镍钴的NCM622在多个循环中比裸NCM622保留了更高的比容量。特别是，0.3 wt%硫化镍钴涂覆的NCM622在15 mA/g的电流密度下循环20次后容量保持率为60.6%，而裸NCM622仅为37.3%。最后，界面XPS和透射电子显微镜-电子能量损失谱分析证实了0.3 wt%硫化镍钴涂覆的NCM622处于稳定状态，副反应极少。
