Simultaneous Interphase Optimizations on the Large-Area
Anode and Cathode of High-Energy-Density Lithium-Ion Pouch Cells by
a Multiple Additives Strategy
posted on 2020-10-01, 02:43authored byXu-Feng Zang, Zhendong Li, Yishan Fang, Yanping Hong, Shengchen Yang, Zhe Peng, Shanshan Sun
Prior
to the maturation of next-generation energy storage devices,
the actual lithium-ion batteries for commercial purposes are still
expected to fulfill some critical requirements, among which the high
energy density, wide operating temperature range, and related long-term
cycling stability are the most challenging issues. Herein a multiple
additives strategy is employed to simultaneously optimize the solid
electrolyte interphase on the large-area anode and cathode in a 2
Ah artificial graphite (AGr)/LiNi0.5Co0.2Mn0.3O2 (NCM523) pouch cell with high gravimetric
(>260 Wh kg–1) and volumetric (>630 Wh L–1) energy density. By introducing a rational mixture
of electrolyte
additives, a highly sulfurized surface layer and a uniform and thin
passivation layer are separately formed on the anode and cathode of
the AGr/NCM523 pouch cell, exhibiting high storage stability at 60
°C, much improved discharge capacity at −10 and −20
°C, high anodic stability at high voltage of 4.4 V, and stable
cyclic performance with a capacity retention of 85.5% after 500 cycles,
significantly outperforming the value of 75.7% after only 200 cycles
of the cell without additional additives. These results demonstrate
the critical effect of simultaneous optimizations of anode and cathode
interphase layers to construct stable high-energy-density lithium-ion
pouch cells.