Fundamental phenomena in anode-free coin cells and pouch cells configured with imide salt-based ether electrolytes

Ether electrolytes are chemically stable against Li-metal. However, the enormous capacity discrepancies between coin cell and pouch cell systems with imide salt-based ether electrolytes are unclear yet. Herein, the fundamental phenomena that cause capacity disparity between anode-free NMC532 parallel to Cu coin cell and pouch cell systems configured with imide salt-based ether electrolytes are systematically investigated by probing the cross-talk effects of transition metals at the anode side. Meanwhile, the corrosion mechanism of stainless steel (SS) coin cells is clarified in detail. The higher accumulation of Ni (6.2), Cr (8.5), and Fe (34.9 ppm) metals on the anode surface after 15 cycles of the NMC532 parallel to Cu coin cell indicates that cross-take of metals is the main source of irreversible coulombic efficiency (>10.4%). NMC532 parallel to Cu pouch cells, on the other hand, provided greater average CE (99.1%) after the 120(th) cycle and only similar to 0.3 ppm Ni was detected, originated from the cathode. The results proved that at high cell voltages, imide salt-based ether electrolytes seriously corrode SS coin cells, resulting in crossover of metals to the anode surface. This work clarifies the corrosion mechanism of SS coin cells and explores anode-free pouch cells for the actual designing of ether electrolytes. (c) 2023 Elsevier Ltd. All rights reserved.