Surpassing the conductivity-conversion trade-off in plasticizer-rich poly(1,3-dioxolane) electrolytes via an efficient initiator

Achieving high monomer conversion of 1,3-dioxolane (DOL) enhances the electrochemical stability of PDOL-based electrolytes, while the reduced liquid contents lead to low ionic conductivity. Addition of plasticizers mitigates the conductivity decrease, yet renders decreased monomer conversion. To address this dilemma, a novel gel polymer electrolyte (In-GPE) was developed via in situ polymerization of plasticizer-rich DOL electrolyte using a highly efficient initiator, i.e., indium trifluoromethanesulphonate (In(OTf) 3 ). The In(OTf) 3 can also be reduced to metallic indium (In), which promotes the interfacial alloying with Li metal with significantly lower Li + binding energy. The incorporation of plasticizers simultaneously enhances the electrochemical window and ionic conductivity of the resulting electrolytes. The In-GPE exhibits a wide electrochemical window (∼4.5 V), high ionic conductivity of 5.14 × 10 −4 S cm −1 , and a superior stable interface. The assembled Li/In-GPE/LFP cell exhibited ultralong cycle performance over 3000 and 2000 cycles at 1 and 2 C, respectively. Meanwhile, even increasing the voltage to 4.2 V, the Li/In-GPE/LFP cell maintained the reversible capacity of 128.9 mA h g −1 at 1 C for 500 cycles. The high-voltage Li/In-GPE/NCM811 cell also delivers excellent cycling performance. The design principle of PDOL-based GPE via a highly efficient initiator in a plasticizer-rich system provides a new pathway to the large-scale application of polymer electrolyte with superior electrochemical performance.