Single Lithium Ion Conducting “Binderlyte” for High‐Performing Lithium Metal Batteries

Abstract Rechargeable lithium metal batteries (LMBs) are deemed as a viable solution to improve the power and/or energy density of the contemporary lithium‐ion batteries (LIBs). However, poor Li‐ion diffusivity within high‐energy cathodes causes sluggish kinetics of the corresponding redox reactions particularly at high C‐rates, thereby largely impeding the performance of rechargeable LMBs. In this work, a dual‐functional single Li‐ion conducting polysalt is proposed as both catholyte and binding agent (coined “Binderlyte”) for rechargeable LMBs. The designed Binderlyte is thermally and electrochemically stable, allowing its use for high‐energy cathodes like Li(Ni_1/3Mn_1/3Co_1/3)O₂ (NMC111). The implementation of designer Binderlyte endows the Li° || NMC111 cell with superior cycling stability and capacity retention even at an extremely high C‐rate of 10C. In particular, the soft and flexible nature of the Binderlyte allows the thick NMC cathode to operate at extremely low porosity (20 vol%) with almost no capacity decay. This work may provide a paradigm shift on the design of innovative polymeric materials, which are essential for developing high‐performing rechargeable LMBs.