The poor cycling stability of graphite in traditional ester electrolyte limits its applications as anodes for potassium ion batteries(KIBs).Herein,we demonstrate that the introduction of cyclic ether co-solvents into ...The poor cycling stability of graphite in traditional ester electrolyte limits its applications as anodes for potassium ion batteries(KIBs).Herein,we demonstrate that the introduction of cyclic ether co-solvents into ester electrolytes can remarkably enhance the cycling stability of graphite anodes.The graphite anode in ester electrolyte with cyclic ether could achieve a reversible capacity of 196.1 m Ah g^(-1) after 100 cycles at 0.3 C(1 C=280 m A g^(-1)),about three times higher than those in ester electrolytes with or without linear ether.Compared with the SEI formed in ester electrolytes,the addition of tetrahydrofuran promotes the generation of K_(2)CO_(3) and ethylene oxide oligomers(PEO),of which the K_(2)CO_(3) is expected to be more conductive and PEO is mechanically robust.The more uniform,conductive and stable solid electrolyte interphases(SEIs)on graphite in electrolytes with cyclic ethers contribute to the enhancement of the electrochemical performances of graphite.This work provides a novel design of commercialized electrolytes to achieve high-performance anodes for KIBs,which potentially accelerates the development of KIBs.展开更多
To tackle undesirable shuttle reaction and sluggish reaction kinetics in lithium–sulfur(Li–S)batteries,we develop a porous and high-density oxygen-doped tantalum nitride nanostructure(nano-TaNO)as an efficient catal...To tackle undesirable shuttle reaction and sluggish reaction kinetics in lithium–sulfur(Li–S)batteries,we develop a porous and high-density oxygen-doped tantalum nitride nanostructure(nano-TaNO)as an efficient catalyst through delicate tailoring.Benefiting from well-defined interior and surface nanopore channels,the nano-TaNO favors abundant sulfur storage,easy electrolyte infiltration and good electrons/Li+transport.More importantly,high-density O dopant in nano-TaNO not only provides high conductivity,but also promotes polysulfide adsorption/conversion via Li–O chemical interactions and the generation of S3∗−radicals to activate additional evolution path from S8 to Li_(2)S.Consequently,the nano-TaNObased cathode exhibits excellent specific capacity and cyclability even under high sulfur loading condition.These interesting findings suggest the great potential of tantalum nitride and a high amount of anion doping engineering in manipulating intermediates and building high-performance Li−S rechargeable batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(U21A2081,22075074,22179014)the Outstanding Young Scientists Research Funds from Hunan Province(2020JJ2004)+2 种基金the Major Science and Technology Program of Hunan Province(2020WK2013)the Natural Science Foundation of Hunan Province(2021JJ40047)the State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(P2022-020)。
文摘The poor cycling stability of graphite in traditional ester electrolyte limits its applications as anodes for potassium ion batteries(KIBs).Herein,we demonstrate that the introduction of cyclic ether co-solvents into ester electrolytes can remarkably enhance the cycling stability of graphite anodes.The graphite anode in ester electrolyte with cyclic ether could achieve a reversible capacity of 196.1 m Ah g^(-1) after 100 cycles at 0.3 C(1 C=280 m A g^(-1)),about three times higher than those in ester electrolytes with or without linear ether.Compared with the SEI formed in ester electrolytes,the addition of tetrahydrofuran promotes the generation of K_(2)CO_(3) and ethylene oxide oligomers(PEO),of which the K_(2)CO_(3) is expected to be more conductive and PEO is mechanically robust.The more uniform,conductive and stable solid electrolyte interphases(SEIs)on graphite in electrolytes with cyclic ethers contribute to the enhancement of the electrochemical performances of graphite.This work provides a novel design of commercialized electrolytes to achieve high-performance anodes for KIBs,which potentially accelerates the development of KIBs.
基金financially supported by the National Natural Science Foundation of China(21601137,51972238,U21A2081,and 22105147)the Basic Science and Technology Research Project of Wenzhou,Zhejiang Province(G20190007)the Special Basic Cooperative Research Programs of Yunnan Provincial Undergraduate Universities Association(202101BA070001-042)。
文摘合理地设计和制备低成本、高效、稳定的非贵金属基碳纳米材料具有重要意义.本文中我们在不同温度条件下,通过有机配体交换将MOF-5转换为ZIF-8,其过程中可以捕捉到ZIF-8的中间态(ZIF-8-M)并得到最终态(ZIF-8-F).将掺杂Fe离子的MOF材料进行热解后,得到的Fe-ZIF-8-F-900材料具有大的比表面积、高的石墨化程度、丰富的碳纳米管以及高活性的铁物种等优点.这些特性有助于后续氧还原反应(ORR)更好的电子转移和质量传输.与Pt/C相比,Fe-ZIF-8-F-900具有优异的ORR性能,如较正的起始电位(0.982 V),大的极限电流密度(5.41 mA cm^(-2))和较小的Tafel斜率(40.6 mV dec^(-1)),且在10小时后电流保持率仍高达94.4%.此外,实验和理论结果均证实了Fe-ZIF-8-F-900组装的锌空气电池在实际应用中表现优异.本研究将为高效、低成本的非贵金属基电催化剂的开发和制备提供合理的设计策略,并为其在能源相关领域的实际应用指明方向.
基金This work was supported in part by the National Natural Science Foundation of China(Nos.22109119,51972238 and U21A2081)the Natural Science Foundation of Zhejiang Province(Nos.LQ19B030006 and LQ22B030003)the Major Scientific and Technological Innovation Project of Wenzhou City(No.ZG2021013).
文摘To tackle undesirable shuttle reaction and sluggish reaction kinetics in lithium–sulfur(Li–S)batteries,we develop a porous and high-density oxygen-doped tantalum nitride nanostructure(nano-TaNO)as an efficient catalyst through delicate tailoring.Benefiting from well-defined interior and surface nanopore channels,the nano-TaNO favors abundant sulfur storage,easy electrolyte infiltration and good electrons/Li+transport.More importantly,high-density O dopant in nano-TaNO not only provides high conductivity,but also promotes polysulfide adsorption/conversion via Li–O chemical interactions and the generation of S3∗−radicals to activate additional evolution path from S8 to Li_(2)S.Consequently,the nano-TaNObased cathode exhibits excellent specific capacity and cyclability even under high sulfur loading condition.These interesting findings suggest the great potential of tantalum nitride and a high amount of anion doping engineering in manipulating intermediates and building high-performance Li−S rechargeable batteries.
