摘要
Lithium-sulfur(Li-S)batteries hold great promise to be the next-generation candidate for high-energy-density secondary batteries but in the prerequisite of using low electrolyte-to-sulfur(E/S)ratios.Highly solvating electrolytes(HSEs)and sparingly solvating electrolytes(SSEs),with opposite nature towards the dissolution of polysulfides,have recently emerged as two effective solutions to decrease the E/S ratio and increase the overall practical energy density of Li-S batteries.HSEs featuring with high polysulfide solvation ability have the potential to reduce the E/S ratio by dissolving more polysulfides with less electrolyte,while SSEs alter the sulfur reaction pathway from a dissolution-precipitation mechanism to a quasi-solid mechanism,thereby independent on the use of electrolyte amount.Both HSEs and SSEs show respective effectiveness in lean-electrolyte Li-S batteries,but encounter different challenges to bring Li-S batteries into practical application.This review aims to present a comparative discussion on their unique features and basic electrochemical reaction mechanisms in practical lean-electrolyte Li-S batteries.Emphasis is focused on the current technical challenges and possible solutions for their future development.
基金
The authors acknowledge the support from the National Natural Science Foundation of China(Nos.U2002213 and 51972219)
the Science and Technology Development Fund Macao SAR(No.0077/2021/A2),the Collaborative Innovation Center of Suzhou Nano Science and Technology,the 111 Project,and the Joint International Research Laboratory of Carbon-based Functional Materials and Devices.
