Preparation And Performance Of Gel Polymer Electrolyte Based On Lignocellulose For Lithium-Sulfur Batteries

Recently,lithium-sulfur batteries have received much attention due to their high theoretical specific capacity(1675 m Ah/g),high theoretical energy density(2600 Wh/kg),and sulfur is abundant,cheap and non-polluting.However,the shuttle effect of soluble polysulfides during the charge-discharge process has seriously limited the development of lithium-sulfur batteries.Gel polymer electrolyte(GPE)can not only effectively inhibit the shuttle effect,but also avoid the safety problem of liquid electrolyte leakage while ensuring the ionic conductivity.In this paper,based on the concept of green environmental protection,the lignocellulose(LC)-based GPE havs been prepared by using the LC as the matrix,treated with NaOH/urea aqueous solution or filled with graphene oxide(GO).They have been systematically evaluated and used to assemble lithium-sulfur batteries to study their battery performances.(1)The modified LC-based GPE has been prepared by partially dissolving the LC in the NaOH/urea aqueous solution at-12 °C with different dissolution times and deionized water cleaning.When the dissolution time is 20 min,the tensile strength is 3.97 MPa,and the ion conductivity of GPE at room temperature is 2.42 m S cm-1.The lithium ion migration number is 0.74,and it has the electrochemical stability window of 1.0-4.9 V and the good electrode compatibility.The assembled lithium-sulfur battery partially suppresses the shuttle effect.(2)Performances of LC-based GPE with different detergents have been investigated.When the detergent is ethanol,the membrane has the liquid absorption rate of 205 wt%,the ion conductivity of 3.66 m S cm-1,and the lithium ion migration number of 0.72,showing the best electrode compatibility and a wide electrochemical stability window.In addition,its lithium-sulfur battery shows the best rate performance and cycle performance.At 80 m A/g,the battery has a specific capacity of 487.2 m Ah/g after 50 cycles.(3)The GO/LC-based GPE has been prepared by solvent evaporation method.The results show that when the GO content is 0.4 wt%,the membrane has the highest liquid absorption,ionic conductivity,and good thermal stability.The assembled battery shows the best rate performance,and the shuttle effect is obviously suppressed within 30 cycles.The preparation methods of the GPE based on LC in this paper are simple and environmentally friendly,which improves the performance of lithium-sulfur batteries and can also provide inspiration for the preparation and application of other gel polymers.