posted on 2021-09-08, 18:08authored byHao Jia, Xianhui Zhang, Yaobin Xu, Lianfeng Zou, Ju-Myung Kim, Peiyuan Gao, Mark H. Engelhard, Qiuyan Li, Chaojiang Niu, Bethany E. Matthews, Teresa L. Lemmon, Jiangtao Hu, Chongmin Wang, Wu Xu
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.