Toward the Practical Use of Cobalt-Free Lithium-Ion Batteries by an Advanced Ether-Based Electrolyte
Hao Jia, Xianhui Zhang, Yaobin Xu, Lianfeng Zou, Ju‐Myung Kim, Peiyuan Gao, Mark Engelhard, Qiuyan Li, Chaojiang Niu, Bethany E. Matthews, Teresa Lemmon, Jiangtao Hu, Chongmin Wang, Wu Xu
Abstract
The criticality of cobalt (Co) has been motivating the quest for Co-free positive electrode materials for building lithium (Li)-ion batteries (LIBs). However, the LIBs based on Co-free positive electrode materials usually suffer from relatively fast capacity decay when coupled with conventional LiPF6-organocarbonate electrolytes. To address this issue, a 1,2-dimethoxyethane-based localized high-concentration electrolyte (LHCE) was developed and evaluated in a Co-free Li-ion cell chemistry (graphite||LiNi0.96Mg0.02Ti0.02O2). Extraordinary capacity retentions were achieved with the LHCE in coin cells (95.3%), single-layer pouch cells (79.4%), and high-capacity loading double-layer pouch cells (70.9%) after being operated within the voltage range of 2.5–4.4 V for 500 charge/discharge cycles. The capacity retentions of counterpart cells using the LiPF6-based conventional electrolyte only reached 61.1, 57.2, and 59.8%, respectively. Mechanistic studies reveal that the superior electrode/electrolyte interphases formed by the LHCE and the intrinsic chemical stability of the LHCE account for the excellent electrochemical performance in the Co-free Li-ion cells.