Boosting the Temperature Adaptability of Lithium Metal Batteries via a Moisture/Acid‐Purified, Ion‐Diffusion Accelerated Separator. Issue 32 (8th July 2022) - Zhang, Min
Abstract: The reliable operation of Li metal batteries suffers from cathode collapse due to high‐voltage cycling, interfacial reactivity of the Li deposits, self‐discharge at the elevated temperatures, as well as the power output deterioration in low‐temperature scenarios. In contrast to the individual electrode optimization, herein, a hetero‐layered separator with an asymmetric functional coating on polyethylene is proposed in response to the aforementioned issues: On the face‐to‐cathode side, the hybrid layer of the molecular sieve and sulfonated melamine formaldehyde can scavenge the hydrofluoric acid and moisture residues from the carbonate electrolyte, maintaining the cathode robustness in both the high‐voltage cycling or high‐temperature storage scenarios; while the pre‐coated Ag2 S layer in situ generates the Li10 Ag3 ‐Li2 S composite matrix in contact with the Li foil, promoting interfacial ion diffusion and isotropic Li deposition. The as‐constructed LiNi0.8 Co0.1 Mn0.1 O2 /Li pouch cell (3.2 Ah) with the hetero‐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 °C). This asymmetric separator strategy enables facile energy‐dense cell prototyping with the commercial electrode/electrolyte. Abstract : A Janus‐faced separator is proposed to stabilize bi‐electrode structures: On the face‐to‐cathode side, a hybrid layer of a molecular sieve and sulfonated melamine formaldehyde can scavenge hydrofluoric acid and moisture from the carbonate electrolyte, suppressing transition metal dissolution of the cathode; while the pre‐coated Ag2 S layer in situ generates an Li10 Ag3 ‐Li2 S interphase layer in contact with Li foil, promoting fast and isotropic ion diffusion.