石墨负极有望应用于钾离子电池,但受到循环过程中不可控的体积波动和枝晶生长的限制.在此,我们利用酰胺基电解质构建了具有高机械强度和离子电导率的阴离子衍生界面,可有效解决这些问题.酰胺分子的高供体数可以加强溶剂分子与K+的溶剂...石墨负极有望应用于钾离子电池,但受到循环过程中不可控的体积波动和枝晶生长的限制.在此,我们利用酰胺基电解质构建了具有高机械强度和离子电导率的阴离子衍生界面,可有效解决这些问题.酰胺分子的高供体数可以加强溶剂分子与K+的溶剂化作用,确保更多的阴离子进入初级溶剂化鞘层.缩短的溶剂与阴离子距离有利于电子从溶剂化的K+转移到阴离子,进而促进阴离子还原.生成的富含无机物的界面缓冲了充放电过程中的体积变化,抑制了K枝晶的生成,促进了钾离子的扩散.基于此,K//K对称电池以0.15 V的极化电位稳定循环超过2800 h.石墨电极实现了C?KC60?KC48?KC36?KC_(2)4?KC8的高度可逆相变,在循环100周后仍保持了217.6 mA h g-1的高放电容量和86.9%的容量保持率.组装的全电池也表现出52.5 W h kg-1的高能量密度.这项工作突出了界面结构的重要性,并为设计高性能电解质提供了全新策略.展开更多
We report the synthesis and electrochemical sodium storage of cobalt disulfide (COS2) with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles (P-CoS2) via a facile solv...We report the synthesis and electrochemical sodium storage of cobalt disulfide (COS2) with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles (P-CoS2) via a facile solvothermal route or nano- octahedrons constructed solid (O-COS2) and hollow microstructures (H-CoS2) fabricated by hydrothermal methods. Among three morphologies, H-CoS2 exhibits the largest discharge capacities and best rate performance as anode of sodium-ion batteries (SIBs). Furthermore, H-CoS2 delivers a capacity of 690 mA.h.g 1 at 1 A·g 1 after 100 cycles in a potential range of 0.1-3.0 V, and N240 mA.h.g-1 over 800 cycles in the potential window of 1.0-3.0 V. This cycling difference mainly lies in the two discharge plateaus observed in 0.1-3.0 V and one discharge plateau in 1.0-3.0 V. To interpret the reactions, X-ray diffraction (XRD) and transmission electron microscopy (TEM) are applied. The results show that at the first plateau around 1.4 V, the insertion reaction (COS2 + xNa* + xe NaxCoS2) Occurs; while at the second plateau around 0.6 V, the conversion reaction (NaxCoS2 + (4 - x) Na+ + (4 - x)e -~ Co + 2Na2S) takes place. This provides insights for electrochemical sodium storage of CoS2 as the anode of SIBs.展开更多
A combined hot-injection and heat-up method was developed to synthesize monodisperse and uniform CoMn2O4 quantum dots (CMO QDs).CMO QDs with average size of 2.0,3.9,and 5.4 nm were selectively obtained at 80,90,and ...A combined hot-injection and heat-up method was developed to synthesize monodisperse and uniform CoMn2O4 quantum dots (CMO QDs).CMO QDs with average size of 2.0,3.9,and 5.4 nm were selectively obtained at 80,90,and 105 ℃,respectively.The CMO QDs supported on carbon nanotubes (CNTs) were employed as catalysts for the oxygen reduction/evolution reaction (ORR/OER) in alkaline solution to investigate their size-performance relationship.The results revealed that the amount of surface-adsorbed oxygen and the band gap energy,which affect the charge transfer in the oxygen electrocatalysis processes,strongly depend on the size of the CMO QDs.The CMO-3.9/CNT hybrid,consisting of CNT-supported CMO QDs of 3.9 nm size,possesses a moderate amount of surfaceadsorbed oxygen,a lower band gap energy,and a larger charge carrier concentration,and exhibits the highest electrocatalytic activity among the hybrid materials investigated.Moreover,the CMO-3.9/CNT hybrid displays ORR and OER performances similar to those of the benchmark Pt/C and RuO2 catalysts,respectively,due to the strong carbon-oxide interactions and the high dispersion of CoMn2O4 QDs on the carbon substrate;this reveals the huge potential of the CMO-3.9/CNT hybrid as a bifunctional OER/ORR electrocatalyst.The present results highlight the importance of controlling the size of metal oxide nanodots in the design of active oxygen electrocatalysts based on spinel-type,nonprecious metal oxides.展开更多
Na-O_(2) and K-O_(2) batteries have attracted extensive attention in recent years.However,the parasitic reactions involving the discharge product of NaO_(2) or K anode with electrolytes and the severe Na or K dendrite...Na-O_(2) and K-O_(2) batteries have attracted extensive attention in recent years.However,the parasitic reactions involving the discharge product of NaO_(2) or K anode with electrolytes and the severe Na or K dendrites plague their rechargeability and cycle stability.Herein,we report a hybrid Na//K^(+)-containing electrolyte//O_(2) battery consisting of a Na anode,1.0 M of potassium trifate in diglyme,and a porous carbon cathode.Upon discharging,KO_(2) is preferentially produced via oxygen reduction in the cathode with Na+stripped from the Na anode,and reversely,the KO_(2) is electrochemically decomposed with Na+plated back onto the anode.Te new reaction pathway can circumvent the parasitic reactions involving instable NaO_(2) and active K anode,and alternatively,the good stability and conductivity of KO_(2) and stable Na stripping/plating in the presence of K^(+) enable the hybrid battery to exhibit an average discharge/charge voltage gap of 0.15 V,high Coulombic efciency of>96%,and superior cycling stability of 120 cycles.Tis will pave a new pathway to promote metal-air batteries.展开更多
基金supported by the National Natural Science Foundation of China(22005082)the Natural Science Foundation of Hebei Province(B2020202065 and E2020202091)+4 种基金Hebei Province Education Department Science and Technology Research Project(QN2020209)the Special Project of Local Science and Technology Development Guided by the Central Government of China(226Z4402G)Shenzhen Science and Technology Program(KQTD20190929173815000)Guangdong Innovative and Entrepreneurial Research Team Program(2019ZT08C044)the Cryo-TEM Center at SUSTech CRF that receives support from the Presidential fund and Development and Reform Commission of Shenzhen Municipality.
文摘石墨负极有望应用于钾离子电池,但受到循环过程中不可控的体积波动和枝晶生长的限制.在此,我们利用酰胺基电解质构建了具有高机械强度和离子电导率的阴离子衍生界面,可有效解决这些问题.酰胺分子的高供体数可以加强溶剂分子与K+的溶剂化作用,确保更多的阴离子进入初级溶剂化鞘层.缩短的溶剂与阴离子距离有利于电子从溶剂化的K+转移到阴离子,进而促进阴离子还原.生成的富含无机物的界面缓冲了充放电过程中的体积变化,抑制了K枝晶的生成,促进了钾离子的扩散.基于此,K//K对称电池以0.15 V的极化电位稳定循环超过2800 h.石墨电极实现了C?KC60?KC48?KC36?KC_(2)4?KC8的高度可逆相变,在循环100周后仍保持了217.6 mA h g-1的高放电容量和86.9%的容量保持率.组装的全电池也表现出52.5 W h kg-1的高能量密度.这项工作突出了界面结构的重要性,并为设计高性能电解质提供了全新策略.
基金This work was supported by the National Natural Science Foundation of China (No. 51231003) and MOE (Nos. B12015 and IRT13R30).
文摘We report the synthesis and electrochemical sodium storage of cobalt disulfide (COS2) with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles (P-CoS2) via a facile solvothermal route or nano- octahedrons constructed solid (O-COS2) and hollow microstructures (H-CoS2) fabricated by hydrothermal methods. Among three morphologies, H-CoS2 exhibits the largest discharge capacities and best rate performance as anode of sodium-ion batteries (SIBs). Furthermore, H-CoS2 delivers a capacity of 690 mA.h.g 1 at 1 A·g 1 after 100 cycles in a potential range of 0.1-3.0 V, and N240 mA.h.g-1 over 800 cycles in the potential window of 1.0-3.0 V. This cycling difference mainly lies in the two discharge plateaus observed in 0.1-3.0 V and one discharge plateau in 1.0-3.0 V. To interpret the reactions, X-ray diffraction (XRD) and transmission electron microscopy (TEM) are applied. The results show that at the first plateau around 1.4 V, the insertion reaction (COS2 + xNa* + xe NaxCoS2) Occurs; while at the second plateau around 0.6 V, the conversion reaction (NaxCoS2 + (4 - x) Na+ + (4 - x)e -~ Co + 2Na2S) takes place. This provides insights for electrochemical sodium storage of CoS2 as the anode of SIBs.
基金This work was supported by the National Key Research and Development Program of China (Nos. 2016YFA0202500 and 2016YFB0101201), the National Natural Science Foundation of China (Nos. 21322101 and 21231005) and 111 Project (Nos. B12015 and IRT13R30).
文摘A combined hot-injection and heat-up method was developed to synthesize monodisperse and uniform CoMn2O4 quantum dots (CMO QDs).CMO QDs with average size of 2.0,3.9,and 5.4 nm were selectively obtained at 80,90,and 105 ℃,respectively.The CMO QDs supported on carbon nanotubes (CNTs) were employed as catalysts for the oxygen reduction/evolution reaction (ORR/OER) in alkaline solution to investigate their size-performance relationship.The results revealed that the amount of surface-adsorbed oxygen and the band gap energy,which affect the charge transfer in the oxygen electrocatalysis processes,strongly depend on the size of the CMO QDs.The CMO-3.9/CNT hybrid,consisting of CNT-supported CMO QDs of 3.9 nm size,possesses a moderate amount of surfaceadsorbed oxygen,a lower band gap energy,and a larger charge carrier concentration,and exhibits the highest electrocatalytic activity among the hybrid materials investigated.Moreover,the CMO-3.9/CNT hybrid displays ORR and OER performances similar to those of the benchmark Pt/C and RuO2 catalysts,respectively,due to the strong carbon-oxide interactions and the high dispersion of CoMn2O4 QDs on the carbon substrate;this reveals the huge potential of the CMO-3.9/CNT hybrid as a bifunctional OER/ORR electrocatalyst.The present results highlight the importance of controlling the size of metal oxide nanodots in the design of active oxygen electrocatalysts based on spinel-type,nonprecious metal oxides.
基金Financial support from National Key R&D Program of China(2017YFA0206700)NSFC(grant No.21603108&51671107)+1 种基金National Natural Science Foundation of ChinaResearch Grants Council of Hong Kong joint project(NSFCRGC project of 51761165025)the 111 project of B12015 is acknowledged.
文摘Na-O_(2) and K-O_(2) batteries have attracted extensive attention in recent years.However,the parasitic reactions involving the discharge product of NaO_(2) or K anode with electrolytes and the severe Na or K dendrites plague their rechargeability and cycle stability.Herein,we report a hybrid Na//K^(+)-containing electrolyte//O_(2) battery consisting of a Na anode,1.0 M of potassium trifate in diglyme,and a porous carbon cathode.Upon discharging,KO_(2) is preferentially produced via oxygen reduction in the cathode with Na+stripped from the Na anode,and reversely,the KO_(2) is electrochemically decomposed with Na+plated back onto the anode.Te new reaction pathway can circumvent the parasitic reactions involving instable NaO_(2) and active K anode,and alternatively,the good stability and conductivity of KO_(2) and stable Na stripping/plating in the presence of K^(+) enable the hybrid battery to exhibit an average discharge/charge voltage gap of 0.15 V,high Coulombic efciency of>96%,and superior cycling stability of 120 cycles.Tis will pave a new pathway to promote metal-air batteries.