Preparation of chitosan and citric acid crosslinked membrane and its application in quasi-solid supercapacitors

Quasi-solid electrolytes promote the development of safe and flexible energy storage devices.In this work,a chitosan and citric acid crosslinked membrane is prepared by a freeze-thaw cross-linking method,in which the chemical crosslinking of chitosan and citric acid increase the viscoelastic behavior of the polymer membrane,and the freeze-thaw assist freeze drying process to create abundant interconnected open-pores and three-dimensional(3D)network.Due to the good viscoelasticity,excellent electrolyte loading capacity(596%)and high ion conductivity(7.7×10^(-3)S·cm^(-)1),as quasi-solid electrolyte,our proposed chitosan and citric acid crosslinked membrane helps ZnICCFT-ZnSO4lAC hybrid supercapacitor to delivers wide operating voltage,high specific capacity of 100.5 F·g^(-1)and stable cycle life(93%after1000 cycles),which suggests that our proposed freezethaw assisted freeze drying method has great potential in designing quasi-solid state electrolyte for energy storage device.

Reasonable suppression of polysulfides/polyselenides shuttle based on MXene in Na-SeS_(2)batteries

Metal-sulfur/selenium batteries have become the focus of new-generation energy storage systems due to the advantages of low-cost and high energy density.However,it still suffers from the notorious shuttle of polysulfides/polyselenides,poor electronic conductivity and tremendous volume expansion.Herein,a dual defense system for polysulfides/polyselenides was proposed and constructed based on MXene.The nitrogen-doped porous carbon(NPC)decorated by Ti_(3)C_(2)T_(x)MXene(M@NPC)was employed as the SeS_(2)host(SeS_(2)@M@NPC).Particularly,Ti_(3)C_(2)T_(x)sheets wrapped on NPC guarantee the rapid ion diffusion and serve as the first barrier for SeS_(2)and dissolved sodium polysulfides/polyselenides.Meanwhile,the few-layered Ti_(3)C_(2)T_(x)sheets coated on glass fiber separators act as the second barrier for alleviating the shuttle of polysulfides/polyselenides through physical interception and chemical adsorption.With this elaborate design,the integrated Na-SeS_(2)battery achieves a high specific capacity of 1243 mAh·g^(-1)at 1.0C,revealing a distinct superiority over its counterparts(SeS_(2)@M@NPC,1083mAh·g^(-1)at 0.5C;and SeS_(2)@NPC,823 mAh·g^(-1)at 0.5C).The findings gained in this work provide a creative idea for the construction of durable room-temperature Na-SeS_(2)batteries based on MXenes and their derivative materials.