Polyfluorinated Crosslinker-based Solid Polymer Electrolytes for Long-Cycling 4.5 V Lithium Metal Batteries

Abstract

Solid polymer electrolytes (SPEs), which are favorable to form intimate interfacial contacts with electrodes, are promising electrolyte of choice for long-cycling lithium metal batteries (LMBs). However, typical SPEs with easily oxidized oxygen-bearing polar groups exhibit narrow electrochemical stability window (ESW), making it impractical to increase specific capacity and energy density of SPE based LMBs with charging cut-off voltage of 4.5 V or higher. Here, a polyfluorinated crosslinker has been applied to enhance oxidation resistance of SPEs via inductive electron-withdrawing effect of polyfluorinated segments transmitted through crosslinked networks. As a result, polyfluorinated crosslinked SPE exhibits a wide ESW, and the Li|SPE|LiNi0.5Co0.2Mn0.3O2 cell with a cutoff voltage of 4.5 V delivers a high discharge specific capacity of ~ 164.19 mAh g− 1 at 0.5 C and capacity retention of ~ 90% after 200 cycles. This work opens a new direction in developing SPEs for long-cycling high-voltage LMBs by using polyfluorinated crosslinking strategy.

Polymer-based electrolytes for solid-state lithium batteries with a wide operating temperature range

“…19 However, the effect of high/low temperatures on polymer-based electrolytes is multidimensional, not only including the physical and electrochemical properties of electrolytes (low temperature ionic conductivity and thermal stability), but also relating to the electrodeelectrolyte interface compatibility (interface stability and destruction). [20][21][22][23] Numerous studies have attempted to overcome these limitations. For instance, Yu and coworkers demonstrated that the ionic conductivity of polymer-based electrolytes could be improved by introducing different dipoles; the asprepared poly(vinyl ethylene carbonate) (PVEC) based polymer electrolyte contained two kinds of dipoles (CQO and C-O) and achieved a high ionic conductivity of 0.4 mS cm À1 @À15 1C.…”

Self-assembled hydrated copper coordination compounds as ionic conductors for room temperature solid-state batteries

“…This work brings new insight on exploring superior room-temperature ionic conductors based on metal coordination compounds.Solid-state lithium-metal batteries (LMBs) comprising Li metal anode and non-combustible solid-state electrolytes (SSEs) are widely recognized as one of the most promising next-generation energy storage systems with both high energy density and superior safety [1][2][3] . As the core component, it is of critical importance to develop highperformance SSEs with high ionic conductivity, extraordinary chemical/electrochemical stability, exceptional electrode compatibility and ease of processing [4][5][6][7][8] .Generally, SSEs can be categorized into two groups: inorganic ceramic electrolytes and organic polymer electrolytes. Inorganic SSEs such as Li 10 GeP 2 S 12 (LGPS), Li 7 La 3 Zr 2 O 12 (LLZO) and Li 1+x Al x Ti 2-x (PO 4 ) 3 (LATP) typically exhibit high ionic conductivity of greater than…”

“…Solid-state lithium-metal batteries (LMBs) comprising Li metal anode and non-combustible solid-state electrolytes (SSEs) are widely recognized as one of the most promising next-generation energy storage systems with both high energy density and superior safety [1][2][3] . As the core component, it is of critical importance to develop highperformance SSEs with high ionic conductivity, extraordinary chemical/electrochemical stability, exceptional electrode compatibility and ease of processing [4][5][6][7][8] .…”