Multiple Strong Ion-Dipole Interactions in Hierarchical Porous Polymer/Covalent Organic Framework Electrolytes...

The development of solid-state lithium metal batteries (SSLMBs) is severely restricted by the inherent drawbacks of conventional solid electrolytes, including sluggish ionic conduction and unstable solid electrolyte interphase (SEI). Herein, we propose a strategy for constructing vinylene-linked covalent organic framework (COF)-based porous composite polymer electrolytes (TFP-COF@PNFs CPEs). The strongly polar -C≡N and -F moieties in TFP-COF form prominent ion-dipole interactions with Li⁺, which reduce the dissociation energy barrier of Li salts, guide the oriented transport of Li⁺, and induce the formation of stable SEI. Therefore, the optimized 2-TFP-COF@PNFs CPEs exhibit a high room-temperature ionic conductivity of 1.68 × 10^{- 3} S cm^{- 1} along with ultra-stable Li||Li symmetric cell cycling exceeding 8500 h. Interestingly, the well-designed CPEs are highly compatible with layered oxides and polyanion compounds; especially, the Li|2-TFP-COF@PNFs|LiFePO₄ full cells deliver a higher initial discharge capacity of 106 mAh g^{- 1} at 10 C with long-term cycling stability after 4000 cycles as well as excellent wide-temperature adaptability (-40°C to 60°C) and compatibility with high mass loadings. Impressively, the assembled pouch cells realize stable cycling for 100 cycles. This work efficiently addresses the core issues of unstable SEI layers and low ionic transport efficiency, offering a highly promising strategy for designing high-performance SSLMBs.