Superwettable Electrolyte Engineering for Fast Charging Li-Ion Batteries

Despite ubiquitous application, lithium-ion batteries (LIBs) still face significant challenges in terms of fast charging over extended cycles. This is primarily due to the incomplete coverage and unsatisfactory performance of the solid electrolyte interphase (SEI) layer. However, conventional electrolyte engineering methods can be hindered by increased viscosity, low wettability, and high cost in growing an ideal SEI. Herein, we propose a general strategy that tackles this challenge using superwettable electrolytes with ultralow concentration, which enables uniform and complete coverage of the SEI on a graphite anode. Intriguingly, this electrolyte can cause high overpotentials during the low-current formation process, leading to an SEI layer rich in inorganic components. As a result, LIBs with superwettable electrolytes exhibit remarkable cycle stability and high-rate performance of 5 C at a capacity of 166 mAh g–1, which is also verified in pouch cells. Our research introduces a simple and effective strategy to achieve an optimized SEI layer for LIBs, which can be readily extended to other battery systems.