Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enha...Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enhancement of its rate capability and cycling stability,especially at high current densities.In this work,we construct one-dimensional Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers by electrospinning method to enhance the kinetic,which realizes high cycling stability.Carbon coating enhances the structure stability,insertion/extraction reversibility of Li-ions and electrochemical reaction activity,and facilitates the transfer of Li-ions.Benefited from the unique architecture and component,the Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows an excellent rate capability with a reversible de-lithiation capacity of 370.8,290.6,269.2,254.3 and 244.9 m Ah g^(-1) at 200,300,500,800 and 1000 m A g^(-1),respectively.Even at a higher current density of 1 A g^(-1),Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows high cycling stability with an initial de-lithiation capacity of 237.8 m Ah g^(-1) and a capacity retention rate of about 84%after 500 cycles.The density functional theory calculation result confirms that the introduction of carbon on the surface of Li_(5)Cr_(7)Ti_(6)O_(25) changes the total density of states of Li_(5)Cr_(7)Ti_(6)O_(25),and thus improves electronic conductivity of the composite,resulting in a good electrochemical performance of Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers.Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers indicate a great potential as an anode material for the next generation of high-performance LIBs.展开更多
Al-ion batteries(AIBs) have been identified as one of the most hopeful energy storage systems after Li-ion batteries on account for the ultrahigh volumetric capacity,high safety and low cost from the rich abundance of...Al-ion batteries(AIBs) have been identified as one of the most hopeful energy storage systems after Li-ion batteries on account for the ultrahigh volumetric capacity,high safety and low cost from the rich abundance of Al.Nonetheless,some inevitable shortcomings,such as the formation of passive oxide film,hydrogen side reactions and anode corrosion,finally limit the large-scale application of aqueous AIBs.The nonaqueous AIBs have been considered as one of most hopeful alternatives for high-powered electrochemical energy storage devices.Nonetheless,various technical and scientific obstacles should be resolved because nonaqueous AIBs are still nascent.Some significant efforts have aimed to resolve these issues towards large-scale applications,and some important advancement has been made.In the present review,we mainly intended to offer an overview of non-aqueous AIBs systems,and we comprehensively reviewed the recent research advancement of the cathode materials,anode materials electrolyte and collectors as well as the fundamental understanding of the functional mechanisms.In addition,we have also analyzed several technical challenges and summarized the strategies used for overcoming the challenges in improving the electrochemical properties,including morphology control,surface engineering,doping and construction of composite electrodes as well as the charge storage mechanisms of the materials with different crystal structures.At last,future research orientation and development prospect of the AIBs are proposed.展开更多
基金supported by the National Natural Science Foundation of China(U1960107)the“333”Talent Project of Hebei Province(A202005018)+1 种基金the Fundamental Research Funds for the Central Universities(N2123034 and N2123001)Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021201)。
文摘Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enhancement of its rate capability and cycling stability,especially at high current densities.In this work,we construct one-dimensional Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers by electrospinning method to enhance the kinetic,which realizes high cycling stability.Carbon coating enhances the structure stability,insertion/extraction reversibility of Li-ions and electrochemical reaction activity,and facilitates the transfer of Li-ions.Benefited from the unique architecture and component,the Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows an excellent rate capability with a reversible de-lithiation capacity of 370.8,290.6,269.2,254.3 and 244.9 m Ah g^(-1) at 200,300,500,800 and 1000 m A g^(-1),respectively.Even at a higher current density of 1 A g^(-1),Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows high cycling stability with an initial de-lithiation capacity of 237.8 m Ah g^(-1) and a capacity retention rate of about 84%after 500 cycles.The density functional theory calculation result confirms that the introduction of carbon on the surface of Li_(5)Cr_(7)Ti_(6)O_(25) changes the total density of states of Li_(5)Cr_(7)Ti_(6)O_(25),and thus improves electronic conductivity of the composite,resulting in a good electrochemical performance of Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers.Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers indicate a great potential as an anode material for the next generation of high-performance LIBs.
基金financially supported by the National Natural Science Foundation of China(nos.U1960107 and 51774002)the Fundamental Research Funds for the Central Universities(no.N182304014)。
文摘Al-ion batteries(AIBs) have been identified as one of the most hopeful energy storage systems after Li-ion batteries on account for the ultrahigh volumetric capacity,high safety and low cost from the rich abundance of Al.Nonetheless,some inevitable shortcomings,such as the formation of passive oxide film,hydrogen side reactions and anode corrosion,finally limit the large-scale application of aqueous AIBs.The nonaqueous AIBs have been considered as one of most hopeful alternatives for high-powered electrochemical energy storage devices.Nonetheless,various technical and scientific obstacles should be resolved because nonaqueous AIBs are still nascent.Some significant efforts have aimed to resolve these issues towards large-scale applications,and some important advancement has been made.In the present review,we mainly intended to offer an overview of non-aqueous AIBs systems,and we comprehensively reviewed the recent research advancement of the cathode materials,anode materials electrolyte and collectors as well as the fundamental understanding of the functional mechanisms.In addition,we have also analyzed several technical challenges and summarized the strategies used for overcoming the challenges in improving the electrochemical properties,including morphology control,surface engineering,doping and construction of composite electrodes as well as the charge storage mechanisms of the materials with different crystal structures.At last,future research orientation and development prospect of the AIBs are proposed.
