SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermo...SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermore,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film.As a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was enhanced.Particularly,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),respectively.Our experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).展开更多
In this work,we construct Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(NLTO-L)composites by a simple ball milled process and post-calcination in air atmosphere to improve the electrochemical performance.The thickness of the LiA...In this work,we construct Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(NLTO-L)composites by a simple ball milled process and post-calcination in air atmosphere to improve the electrochemical performance.The thickness of the LiAlO_(2)coating layer is approximate2 nm.The morphology and particle size of Na_(2)Li_(2)Ti_(6)O_(14)are not dramatically altered after LiAlO_(2)coating.All samples display similar particles with a size range from 150 to 500 nm.The LiAlO_(2)coating can supply fast charge transmission paths with good insertion/extraction dynamics of lithium ions and provide an excellent rate performance and cycle performance of as-prepared Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)anodes.Therefore,LiAlO_(2)coating efficiently enhances the rate performance and cycle performance of Na_(2)Li_(2)Ti_(6)O_(14)anode,even at large current densities.As a result,Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(5 wt%)reveals remarkable rate properties with reversible charge capacity of 238.7,214.7,185.8,168.5 and 139.8 mAh g^(-1)at 50,100,200,300 and 500 mA g^(-1),respectively.Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(5 wt%)also possesses a good cycle performance with a de-lithiation capacity of 166.5 mAh g-1 at 500 mA g^(-1)after 200 cycles.Nonetheless,the corresponding de-lithiation capacity of pure Na_(2)Li_(2)Ti_(6)O_(14)is only 140.1 mAh g^(-1).Consequently,LiAlO_(2)coating is efficeient approach to enhance the electrochemical performances of Na_(2)Li_(2)Ti_(6)O_(14).展开更多
Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling sta...Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling stability under high current due to limited diffusion kinetics and poor electrical conductivity.Here,the PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) composites are successfully obtained via the solid-state method and followed by chemical oxidation process in the first time.The results of tests prove that the Na_(2)Li_(2)Ti_(6)O_(14)@PPy composites have better electrochemical performance than the bare Na_(2)Li_(2)Ti_(6)O_(14) because of the excellent electrical conductivity and the special macromolecular architecture of PPy.In particular,the Na_(2) Li_(2) Ti_(6) O_(14) @PPy(4 wt%)exhibits excellent charge capacities of about 223.2,218.0,200.8,184.3 and 172.6 mAh g^(-1) at 50,100,200,300 and500 mA g^(-1),respectively,revealing the best rate capability of all electrode materials.The Na_(2)Li_(2)Ti_(6)O_(14)@PPy(4 wt%)not only has the highest charge capacity under 0.5 mA g^(-1),but also has the highest capacity retention of 85.12%among all samples after 100 loops.Hence,the PPy coating is known as a promising way to improve the electrochemical property of Na_(2)Li_(2)Ti_(6)O_(14).The PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) demonstrates the great prospect as promising negative materials for Li-ion batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(nos.21773060,51774002,and 21601054)Fundamental Research Funds for the Central Universities(no.N182304014)+1 种基金Youth Innovation Team Project of Science and technology of Heilongjiang University(2018-KYYWF-1593)Young Scholar Project of the Long Jiang Scholars Program(Q201818)
文摘SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermore,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film.As a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was enhanced.Particularly,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),respectively.Our experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).
基金supported by the National Natural Science Foundation of China(51404002)Anhui Provincial Natural Science Foundation(1508085MB25)+1 种基金the Natural Science Foundation of Guangdong Province(2016A030310127)Anhui Provincial Science Fund for Excellent Young Scholars(gxyq ZD2016066)
基金financially supported by the National Natural Science Foundation of China(No.U1960107)the“333”Talent Project of Hebei Province(No.A202005018)the Fundamental Research Funds for the Central Universities(No N2123001)。
文摘In this work,we construct Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(NLTO-L)composites by a simple ball milled process and post-calcination in air atmosphere to improve the electrochemical performance.The thickness of the LiAlO_(2)coating layer is approximate2 nm.The morphology and particle size of Na_(2)Li_(2)Ti_(6)O_(14)are not dramatically altered after LiAlO_(2)coating.All samples display similar particles with a size range from 150 to 500 nm.The LiAlO_(2)coating can supply fast charge transmission paths with good insertion/extraction dynamics of lithium ions and provide an excellent rate performance and cycle performance of as-prepared Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)anodes.Therefore,LiAlO_(2)coating efficiently enhances the rate performance and cycle performance of Na_(2)Li_(2)Ti_(6)O_(14)anode,even at large current densities.As a result,Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(5 wt%)reveals remarkable rate properties with reversible charge capacity of 238.7,214.7,185.8,168.5 and 139.8 mAh g^(-1)at 50,100,200,300 and 500 mA g^(-1),respectively.Na_(2)Li_(2)Ti_(6)O_(14)@LiAlO_(2)(5 wt%)also possesses a good cycle performance with a de-lithiation capacity of 166.5 mAh g-1 at 500 mA g^(-1)after 200 cycles.Nonetheless,the corresponding de-lithiation capacity of pure Na_(2)Li_(2)Ti_(6)O_(14)is only 140.1 mAh g^(-1).Consequently,LiAlO_(2)coating is efficeient approach to enhance the electrochemical performances of Na_(2)Li_(2)Ti_(6)O_(14).
基金financially supported by the National Natural Science Foundation of China(No.U1960107)the“333”Talent Project of Hebei Province(No.A202005018)the Fundamental Research Funds for the Central Universities(No.N2123001)。
文摘Na_(2)Li_(2)Ti_(6)O_(14) as a reliable anode material is becoming a hopeful candidate for Li-ion battery.Nevertheless,the pristine Na_(2)Li_(2)Ti_(6)O_(14) usually suffer from bad rate performance and poor cycling stability under high current due to limited diffusion kinetics and poor electrical conductivity.Here,the PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) composites are successfully obtained via the solid-state method and followed by chemical oxidation process in the first time.The results of tests prove that the Na_(2)Li_(2)Ti_(6)O_(14)@PPy composites have better electrochemical performance than the bare Na_(2)Li_(2)Ti_(6)O_(14) because of the excellent electrical conductivity and the special macromolecular architecture of PPy.In particular,the Na_(2) Li_(2) Ti_(6) O_(14) @PPy(4 wt%)exhibits excellent charge capacities of about 223.2,218.0,200.8,184.3 and 172.6 mAh g^(-1) at 50,100,200,300 and500 mA g^(-1),respectively,revealing the best rate capability of all electrode materials.The Na_(2)Li_(2)Ti_(6)O_(14)@PPy(4 wt%)not only has the highest charge capacity under 0.5 mA g^(-1),but also has the highest capacity retention of 85.12%among all samples after 100 loops.Hence,the PPy coating is known as a promising way to improve the electrochemical property of Na_(2)Li_(2)Ti_(6)O_(14).The PPy-coated Na_(2)Li_(2)Ti_(6)O_(14) demonstrates the great prospect as promising negative materials for Li-ion batteries.
