Since lithium sulfur(Li-S)energy storage devices are anticipated to power portable gadgets and electric vehicles owing to their high energy density(2600 Wh·kg^(-1));nevertheless,their usefulness is constrained by...Since lithium sulfur(Li-S)energy storage devices are anticipated to power portable gadgets and electric vehicles owing to their high energy density(2600 Wh·kg^(-1));nevertheless,their usefulness is constrained by sluggish sulfur reaction kinetics and soluble lithium polysulfide(LPS)shuttling effects.High electrically conductive bifunctional electrocatalysts are urgently needed for Li-S batteries,and high-entropy oxide(HEO)is one of the most promising electrocatalysts.In this work,we synthesize titanium-containing high entropy oxide(Ti-HEO)(TiFeNiCoMg)O with enhanced electrical conductivity through calcining metal-organic frameworks(MOF)templates at modest temperatures.The resulting single-phase Ti-HEO with high conductivity could facilitate chemical immobilization and rapid bidirectional conversion of LPS.As a result,the Ti-HEO/S/KB cathode(with 70 wt.%of sulfur)achieves an initial discharge capacity as high as~1375 mAh·g^(-1)at 0.1 C,and a low-capacity fade rate of 0.056%per cycle over 1000 cycles at 0.5 C.With increased sulfur loading(~5.0 mg·cm^(-2)),the typical Li-S cell delivered a high initial discharge capacity of~607 mAh·g^(-1)at 0.2 C and showcased good cycling stability.This work provides better insight into the synthesis of catalytic Ti-containing HEOs with enhanced electrical conductivity,which are effective in simultaneously enhancing the LPS-conversion kinetics and reducing the LPS shuttling effect.展开更多
基金the following financial supports:the National Natural Science Foundation of China(Nos.52372289 and 52102368)Guangdong Science and Technology Bureau(Grant Nos.2019B090908001 and 2020A0505090011)+4 种基金Guangdong Special Fund for Key Areas(20237DZX3042)Shenzhen STI(Grant No.SGDX20190816230615451)Shenzhen Stable Support Project,Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices(Grant No.2019B121205001)Otto Poon Charitable Foundation(Grant Nos.847W,CDBC,CDBW)HKPolyU Postdoctoral Fellowships(Grant No.W28H).
文摘Since lithium sulfur(Li-S)energy storage devices are anticipated to power portable gadgets and electric vehicles owing to their high energy density(2600 Wh·kg^(-1));nevertheless,their usefulness is constrained by sluggish sulfur reaction kinetics and soluble lithium polysulfide(LPS)shuttling effects.High electrically conductive bifunctional electrocatalysts are urgently needed for Li-S batteries,and high-entropy oxide(HEO)is one of the most promising electrocatalysts.In this work,we synthesize titanium-containing high entropy oxide(Ti-HEO)(TiFeNiCoMg)O with enhanced electrical conductivity through calcining metal-organic frameworks(MOF)templates at modest temperatures.The resulting single-phase Ti-HEO with high conductivity could facilitate chemical immobilization and rapid bidirectional conversion of LPS.As a result,the Ti-HEO/S/KB cathode(with 70 wt.%of sulfur)achieves an initial discharge capacity as high as~1375 mAh·g^(-1)at 0.1 C,and a low-capacity fade rate of 0.056%per cycle over 1000 cycles at 0.5 C.With increased sulfur loading(~5.0 mg·cm^(-2)),the typical Li-S cell delivered a high initial discharge capacity of~607 mAh·g^(-1)at 0.2 C and showcased good cycling stability.This work provides better insight into the synthesis of catalytic Ti-containing HEOs with enhanced electrical conductivity,which are effective in simultaneously enhancing the LPS-conversion kinetics and reducing the LPS shuttling effect.
