Bridging Evolution of the Solvation Sheath to Rigid‐Soft Coupling and Low‐Resistance Solid Electrolyte Interface for Fast‐Charging and Ultrastable Bi Anode

Abstract

AbstractThe key issue holding back the application of Bi‐based lithium‐ion battery (LIB) is the rigorous requirements of low interfacial resistance, superior mechanical stability, and high ion conductivity of solid electrolyte interface (SEI). In this work, inspired by human musculoskeletal tissues, a multifunctional SEI with low interfacial resistance and synergistic rigid‐soft features is in situ constructed through the interfacial evolution of PF6 anion‐derived solvation sheath at the Bi anode, facilitating Li ion conductivity, and SEI/electrolyte interface wettability, alleviating the enormous volumetric expansion of Bi anodes, and offering superior Bi/SEI/electrolyte compatibility during long‐term cycles. Attributed to these superiorities, an unprecedented cycling stability can be obtained, i.e., 94.4% capacity retention at 2.6 C after 1000 cycles and 89.6% capacity retention at 5.2 C after 1300 cycles. When this anode is coupled with a LiFePO4 cathode, the full cell delivers superior cyclability with 85.2% capacity retention at 0.6 C after 100 cycles. This research provides new insight into handling the interfacial compatibility and fast‐charging issues of Bi‐based LIB.