Promoted Li+ Desolvation by the Reconstruction of Hydrogen-Bond Network in Functional Separator to Stabilize the Lithium Metal Anode Interface

Abstract

High energy density lithium metal batteries (LMBs) are challenged by unstable interface reactions, leading to the continuous deterioration of parasitic reactions. To overcome this problem, here, new strategies are designed for promoting Li⁺ desolvation (PLD) separators with modulated hydrogen-bond network to stabilize the interfacial reaction. Experimental and computational results show that the difference in the electron cloud density distribution on the separator surface not only breaks the hydrogen-bond network of the conventional carbonate electrolyte, thus capturing the strongly dissolved ethylene carbonate (EC) but also realizes the promoted desolvation process of the outer Helmholtz plane (OHP). As a result, the Li⁺ desolvation barrier of the PLD separator decreases from 81.15 kJ to 73.01 kJ mol⁻¹. The long cycle life of the assembled Li/Li symmetric cell with PLD separator can be extended to 4500 h at 3 mA cm⁻²/1.5 mAh cm⁻². Notably, the LFP/Li full cell with the PLD separator even achieves a specific capacity of 94.2 mAh g⁻¹ at a high rate of 7C. These results demonstrate that the PLD separator is capable of stabilizing interfacial reactions and enhancing the performance of high-rate LMBs, providing new ideas for further rational development in this field.