Boosting the Temperature Adaptability of Lithium Metal Batteries via a Moisture/Acid-Purified, Ion-Diffusion Accelerated Separator

摘要

The reliable operation of Li metal batteries suffers from cathode collapse dueto high-voltage cycling, interfacial reactivity of the Li deposits, self-dischargeat the elevated temperatures, as well as the power output deterioration inlow-temperature scenarios. In contrast to the individual electrode optimization,herein, a hetero-layered separator with an asymmetric functional coatingon polyethylene is proposed in response to the aforementioned issues: On theface-to-cathode side, the hybrid layer of the molecular sieve and sulfonatedmelamine formaldehyde can scavenge the hydrofluoric acid and moistureresidues from the carbonate electrolyte, maintaining the cathode robustnessin both the high-voltage cycling or high-temperature storage scenarios; whilethe pre-coated Ag_2S layer in situ generates the Li10Ag3-Li2S composite matrix incontact with the Li foil, promoting interfacial ion diffusion and isotropic Li deposition.The as-constructed LiNi_(0.8)Co_(0.1)Mn_(0.1）O_2/Li pouch cell (3.2 Ah) with thehetero-layered separator can achieve a high energy density of 400.6 Wh kg~(?1)on the cell level, as well as a wider temperature adaptability (0–75 ℃). Thisasymmetric separator strategy enables facile energy-dense cell prototypingwith the commercial electrode/electrolyte.