Lithium‐Ion Batteries with Superlong Cycle‐Life in Wide Temperature Range via Interfacial Alkyl‐Chain Sway

The cathode-electrolyte interphase directly influences the wide-temperature performance of lithium-ion batteries, particularly long-term cycle performance. However, improving both high- and low-temperature properties of cathode often requires distinct approaches, making it challenging to unify these strategies. In this work, an interfacial-driven strategy on the cathode surface is designed with nano-Mg(OH)2 with Tween80 (nano-Mg(OH)2@Tween80). Tween80 serves as the framework of the weak-linked flexible confined space for preparing ultrafine nano-Mg(OH)2 and then adsorbs in situ onto the nano-Mg(OH)2. In the cell assembled with nano-Mg(OH)2@Tween80 modified LiNi0.5Co0.2Mn0.3O2, the alkyl-chain sway of Tween80 molecules accelerates electrolyte diffusion on cathode surface. Hence, both the timely formation of a stable and conductive Mg-rich interphase layer and rapid lithium-ion transfer are achieved, leading to the co-improvement of high/low-temperature performances. The half-cell with the addition of nano-Mg(OH)2@Tween80, maintains over 70 mAh·g-1 and 90% Coulombic efficiency after 1000 cycles at 60 °C, and keeps 80 mAh·g-1 with 99% Coulombic efficiency after 500 cycles at -5 °C, even still very stable at -15 °C.