Phosphorus is a promising anode with high capacity (2596 mAh g^(-1)and 6075~6924 mAh cm^(-3)),low lithium-ion diffusion barrier (0.08 e V),and appropriate lithiation potential (~0.7 V vs Li+/Li).However,it faces the p...Phosphorus is a promising anode with high capacity (2596 mAh g^(-1)and 6075~6924 mAh cm^(-3)),low lithium-ion diffusion barrier (0.08 e V),and appropriate lithiation potential (~0.7 V vs Li+/Li).However,it faces the problems of huge volume expansion (~300%),low electronic conductivity (10^(-14)~10^(2)S cm^(-1)),soluble intermediates (lithium polyphosphides,Li_(x)Ps),degradation in air,and low thermal stability.In this work,phosphorus/carbon nanotube composites were coated with a polyimide layer,which plays the roles of a buffer layer to relieve the volume expansion of phosphorus,an obstruct layer to confine LixPs,an inert layer to prevent the degradation of phosphorus in air,a heat resistant layer to improve the thermal stability of the anode.The resulting composites (P/CNT@PI) display high capacity retention of798.1 m Ah g^(-1)after 150 cycles at 1 A g^(-1),achieving 17 times as much as the control sample (P/CNT).展开更多
FePS3,a classical 2D layered material with transition metal phosphorous trichalcogenides,was investigated as an anode material for Mg ion batteries.We used density functional theory to calculate the Mg storage propert...FePS3,a classical 2D layered material with transition metal phosphorous trichalcogenides,was investigated as an anode material for Mg ion batteries.We used density functional theory to calculate the Mg storage properties of FePS3,such as Mg adsorption energy,theoretical specific capacity,average voltage,diffusion energy barriers,volume change,and electronic conductivity.The theoretical specific capacity of the FePS3 monolayer is 585.6 mA h/g with a relatively low average voltage of 0.483 V(vs.Mg/Mg^2+),which is favorable to a high energy density.The slight change in volume and good electronic conductivity of bulk FePS 3 are beneficial to electrode stability during cycling.展开更多
二维(2D)材料MXenes由于具有金属导电性以及种类丰富的表面终止基团,在储能材料领域得到广泛研究.MXenes片层之间存在空隙,能够提供快速的离子传输通道,实现高倍率性能,并且进一步剥离的MXenes能够提供更多的离子储存位点.然而,剥离的MX...二维(2D)材料MXenes由于具有金属导电性以及种类丰富的表面终止基团,在储能材料领域得到广泛研究.MXenes片层之间存在空隙,能够提供快速的离子传输通道,实现高倍率性能,并且进一步剥离的MXenes能够提供更多的离子储存位点.然而,剥离的MXenes纳米片存在着严重的重新堆叠情况,导致电化学性能降低.为了解决该问题,本文提出了一种借助四丁基铵离子(TBA+)修饰,使均带负电的剥离Ti_(3)C_(2)T_(x)(MXenes)和氧化石墨烯(GO)纳米片通过静电自组装再退火的策略,制备结构稳定的Ti_(3)C_(2)T_(x)/rGO复合纳米材料.Ti_(3)C_(2)T_(x)与rGO纳米片以面对面的结构排布,分散均匀且能够缓解MXenes纳米片重新堆叠的情况,增大了电极材料的电化学活性面积,因此能够提供高的可逆比容量(1394 mAh g^(-1))和优越的倍率性能.同时与活性碳作为正极组装成锂离子电容器,能量密度最高可达145 Wh kg^(-1),循环5000次后的容量保持率>80%,充分证明了Ti_(3)C_(2)T_(x)/rGO作为锂离子电容器电极材料的潜力.展开更多
基金the support sponsored by the National Key Research and Development Program of China(2019YFE0118800)the National Natural Science Foundation of China(22005215)the Hebei Province Innovation Ability Promotion Project(20544401D,20312201D)。
文摘Phosphorus is a promising anode with high capacity (2596 mAh g^(-1)and 6075~6924 mAh cm^(-3)),low lithium-ion diffusion barrier (0.08 e V),and appropriate lithiation potential (~0.7 V vs Li+/Li).However,it faces the problems of huge volume expansion (~300%),low electronic conductivity (10^(-14)~10^(2)S cm^(-1)),soluble intermediates (lithium polyphosphides,Li_(x)Ps),degradation in air,and low thermal stability.In this work,phosphorus/carbon nanotube composites were coated with a polyimide layer,which plays the roles of a buffer layer to relieve the volume expansion of phosphorus,an obstruct layer to confine LixPs,an inert layer to prevent the degradation of phosphorus in air,a heat resistant layer to improve the thermal stability of the anode.The resulting composites (P/CNT@PI) display high capacity retention of798.1 m Ah g^(-1)after 150 cycles at 1 A g^(-1),achieving 17 times as much as the control sample (P/CNT).
基金supported by Tianjin Science and Technology Project(19YFSLQY00070)the National Natural Science Foundation of China(No.21878216)the Opening Foundation of State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology(oic-201901004,oic-201801003).
文摘FePS3,a classical 2D layered material with transition metal phosphorous trichalcogenides,was investigated as an anode material for Mg ion batteries.We used density functional theory to calculate the Mg storage properties of FePS3,such as Mg adsorption energy,theoretical specific capacity,average voltage,diffusion energy barriers,volume change,and electronic conductivity.The theoretical specific capacity of the FePS3 monolayer is 585.6 mA h/g with a relatively low average voltage of 0.483 V(vs.Mg/Mg^2+),which is favorable to a high energy density.The slight change in volume and good electronic conductivity of bulk FePS 3 are beneficial to electrode stability during cycling.
基金supported by the National Natural Science Foundation of China (51677182 and 51822706)the Dalian National Laboratory for Clean Energy (DNL) Cooperation Fund, CAS (DNL201915 and DNL201912)+1 种基金the Beijing Municipal Science and Technology Commission (Z181100000118006)the Key Research Program of Frontier Sciences, CAS (ZDBS-LY-JSC047)。
文摘二维(2D)材料MXenes由于具有金属导电性以及种类丰富的表面终止基团,在储能材料领域得到广泛研究.MXenes片层之间存在空隙,能够提供快速的离子传输通道,实现高倍率性能,并且进一步剥离的MXenes能够提供更多的离子储存位点.然而,剥离的MXenes纳米片存在着严重的重新堆叠情况,导致电化学性能降低.为了解决该问题,本文提出了一种借助四丁基铵离子(TBA+)修饰,使均带负电的剥离Ti_(3)C_(2)T_(x)(MXenes)和氧化石墨烯(GO)纳米片通过静电自组装再退火的策略,制备结构稳定的Ti_(3)C_(2)T_(x)/rGO复合纳米材料.Ti_(3)C_(2)T_(x)与rGO纳米片以面对面的结构排布,分散均匀且能够缓解MXenes纳米片重新堆叠的情况,增大了电极材料的电化学活性面积,因此能够提供高的可逆比容量(1394 mAh g^(-1))和优越的倍率性能.同时与活性碳作为正极组装成锂离子电容器,能量密度最高可达145 Wh kg^(-1),循环5000次后的容量保持率>80%,充分证明了Ti_(3)C_(2)T_(x)/rGO作为锂离子电容器电极材料的潜力.
