Organic–Organic Composite Electrolyte Enables Ultralong Cycle Life in Solid-State Lithium Metal Batteries

Abstract

Ionic conducting polymer electrolytes for solid-state lithium-ion batteries have attracted ever-increasing attention because of their decent ionic conductivity, flexibility, no liquid leakage, and good processability. Poly­(vinylidene fluoride) (PVDF)-based polymer electrolytes have recently stood out among the polymer electrolytes due to their high room temperature ionic conductivity. However, the interface between PVDF-based polymer electrolytes and lithium metal decays over time until the batteries break down. Here, we introduce a small amount of poly­(acrylic acid) (PAA) into a PVDF-based polymer electrolyte and synthesize an organic–organic composite electrolyte that alleviates the interfacial reaction with lithium metal, which shows great superiority over other modification methods such as coating. The cycle life of lithium symmetric cells is prolonged from 130 to 850 h at 0.44 mA cm–2 due to the effective suppression of interfacial reaction. The much more stable interface also enables excellent cycle performance in a solid-state LiCoO2||Li cell at 30 °C with a capacity decay of 0.03% per cycle for 1000 cycles, which is much lower than that of a cell without blending PAA (0.13% per cycle for only 450 cycles). The results would shed light on the applications of PVDF-based polymer electrolytes in solid-state lithium metal batteries.

Toward High Performance All‐Solid‐State Lithium Batteries with High‐Voltage Cathode Materials: Design Strategies for Solid Electrolytes, Cathode Interfaces, and Composite Electrodes

“…Generally, sheet‐type electrodes for polymer‐based ASSLBs are easier to obtain because polymer‐based SEs possess good film‐forming properties and can directly act as the binders. [ 65b,82a,194 ] However, for their sulfide‐based/oxide‐based counterparts, additional polymeric binders are indispensable for the preparation of large sheet‐type electrodes. [ 195 ] Unfortunately, the available binders for sulfide‐based ASSLBs are limited by the solvents due to the severe reactivity of sulfide‐based SEs with common polar solvents.…”

Macromolecular Design of Lithium Conductive Polymer as Electrolyte for Solid‐State Lithium Batteries

“…Moreover, the strong inter‐ and intra‐molecular force of the fluorine groups induces an improvement in the mechanical properties of polymer matrix. As a result, PVDF is usually employed as polymer matrix in blended SPE [ 44 ] and composite polymer electrolyte (CPE) [ 45,46 ] to benefit from those advantages. Furthermore, when the current density is increasing, an in situ interface layer generates between lithium anode and PVDF‐based SPE to avoid the risk of over‐current.…”

Three-dimensional thiophene-diketopyrrolopyrrole-based molecules/graphene aerogel as high-performance anode material for lithium-ion batteries

“…[3][4][5] Among them, organic electrode materials have attracted much attention for their high power density, simple and easy availability of raw materials, and environmental friendliness. 2,6,7 Because of their different structures and tunable redox voltages, conjugated carbonyl compounds are one of the most attractive classes of organic electrode materials in the family. 8,9 Since the majority of them possess relatively high redox potentials, they are oen used as cathode materials.…”