材料科学
阴极
电化学
电解质
锂(药物)
法拉第效率
镍
电化学窗口
溶解
化学工程
电池(电)
电极
冶金
离子电导率
物理化学
工程类
内分泌学
物理
功率(物理)
化学
医学
量子力学
作者
Seok Hyun Song,Moses Azong Cho,In-Chul Park,Jong Gyu Yoo,K.-T. Ko,Jihyun Hong,Jongsoon Kim,Sung Kyun Jung,Maxim Avdeev,Sungdae Ji,Seongsu Lee,Joona Bang,Hyungsub Kim
标识
DOI:10.1002/aenm.202000521
摘要
Abstract Layered lithium–nickel–cobalt–manganese oxide (NCM) materials have emerged as promising alternative cathode materials owing to their high energy density and electrochemical stability. Although high reversible capacity has been achieved for Ni‐rich NCM materials when charged beyond 4.2 V versus Li + /Li, full lithium utilization is hindered by the pronounced structural degradation and electrolyte decomposition. Herein, the unexpected realization of sustained working voltage as well as improved electrochemical performance upon electrochemical cycling at a high operating voltage of 4.9 V in the Ni‐rich NCM LiNi 0.895 Co 0.085 Mn 0.02 O 2 is presented. The improved electrochemical performance at a high working voltage at 4.9 V is attributed to the removal of the resistive Ni 2+ O rock‐salt surface layer, which stabilizes the voltage profile and improves retention of the energy density during electrochemical cycling. The manifestation of the layered Ni 2+ O rock‐salt phase along with the structural evolution related to the metal dissolution are probed using in situ X‐ray diffraction, neutron diffraction, transmission electron microscopy, and X‐ray absorption spectroscopy. The findings help unravel the structural complexities associated with high working voltages and offer insight for the design of advanced battery materials, enabling the realization of fully reversible lithium extraction in Ni‐rich NCM materials.
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