先对炭纤维布(CC)进行不同时间的硝酸热处理,随后采用一步溶剂热方法在炭纤维布上沉积NiCo2S4纳米颗粒。结果表明,随着酸处理时间的延长,炭纤维表面粗糙度增加,含氧量增加。当酸处理时间为12 h时,NiCo2S4在其表面负载最均匀,复合材料的...先对炭纤维布(CC)进行不同时间的硝酸热处理,随后采用一步溶剂热方法在炭纤维布上沉积NiCo2S4纳米颗粒。结果表明,随着酸处理时间的延长,炭纤维表面粗糙度增加,含氧量增加。当酸处理时间为12 h时,NiCo2S4在其表面负载最均匀,复合材料的电化学性能最优,在电流密度为1 A g-1时,比容量可达1 298 F g-1,当增大到20 A g-1时,容量仍可保持为原来的89.7%。在5 A g-1电流密度下,循环次数达到3 000次时,容量保持率为95.3%。将所得复合材料作为正极,纳米炭纤维布(CNF)为负极,组装成具有自支撑结构的非对称超级电容器,在功率密度754 W kg-1时,其能量密度可达37.5 Wh kg-1。展开更多
Bimetallic Ni–Co sulfides are outstanding pseudocapacitive materials with high electrochemical activity and excellent energy storage performance as electrodes for high-performance supercapacitors.In this study,a nove...Bimetallic Ni–Co sulfides are outstanding pseudocapacitive materials with high electrochemical activity and excellent energy storage performance as electrodes for high-performance supercapacitors.In this study,a novel urchin-like NiCo2S4@mesocarbon microbead(NCS@MCMB) composite with a core–shell structure was prepared by a facile two-step hydrothermal method.The highly conductive MCMBs offered abundant adsorption sites for the growth of NCS nanoneedles,which allowed each nanoneedle to fully unfold without aggregation,resulting in improved NCS utilization and efficient electron/ion transferin the electrolyte.When applied as an electrode material for supercapacitors,the composite exhibited a maximum specific capacitance of 936 Fg-1 at 1 Ag-1 and a capacitance retention of 94% after 3000 cycles at 5 Ag-1,because of the synergistic effect of MCMB and NCS.Moreover,we fabricated an asymmetric supercapacitor based on the NCS@MCMB composite,which exhibited enlarged voltage windows and could power a light-emitting diode device for several minutes,further demonstrating the exceptional electrochemical performance of the NCS@MCMB composite.展开更多
Urea oxidation is a significant reaction for utilizing urea-rich wastewater or human urine as sustainable power sources which can ease the water eutrophication while generate electricity. A direct urea-hydrogen peroxi...Urea oxidation is a significant reaction for utilizing urea-rich wastewater or human urine as sustainable power sources which can ease the water eutrophication while generate electricity. A direct urea-hydrogen peroxide fuel cell is a new kind of fuel cell employing urea as fuel and hydrogen peroxide as oxidant which possesses a larger cell voltage. Herein, this work tries to promote the kinetics process of urea oxidation by preparing low-cost and high-efficient NiCo2S4 nanowires modified carbon sponge electrode. The carbon sponge used in this work with a similar three-dimensional multi-channel structure to Ni foam, is prepared by carbonizing recycled polyurethane sponge which is also a process of recycling waste. The performance of the prepared catalyst in an alkaline solution is investigated in a three-electrode system.With the introduction of Co element to the catalyst, a reduced initial urea oxidation potential and a high performance are obtained. Furthermore, a direct urea-hydrogen peroxide fuel cell is assembled using the NiCo2S4 nanowires modified carbon sponge anode. Results indicate that the prepared catalyst provides a chance to solve the current problems that hinder the development of urea electrooxidation(high initial urea oxidation potential, low performance, and high electrode costs).展开更多
Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Pol...Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Polyethylene glycol (PEG) 200 and thiourea were used as a shape-control age nt and sulfur source for in-s让u sulfuration, respectively. The urchin-like NiC02S4 was characterized by X-ray powder diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and electrochemical measurements. The resulting NiCo2S4 with ion diffusion-favored structure demonstrated remarkable electrochemical characteristics for supercapacitor with a high specific capacitance (1334F/g at 0.5 A/g) and superior rate capability (78.1% of the original capacity from 0.5 to 20 A/g) in 6M KOH aqueous solution. Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4 as a positive electrode and activated carb on (AC) as a n egative electrode. A NiCo2Sj/AC device exhibited a high energy density of 37.32 Wh/kg at a power density of 317.8 W/kg with capacity retention of 91.9% and up to 2000 charge/discharge cycles at 3 A/g. The results demonstrate that the sea-urchin-like NiCo2S4 has potential applications in supercapacitors.展开更多
采用脉冲激光沉积法制备了NiCo_2S_4薄膜,利用恒流充放电和循环伏安测试研究了NiCo_2S_4薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo_2S_4薄膜首次循环过程中的...采用脉冲激光沉积法制备了NiCo_2S_4薄膜,利用恒流充放电和循环伏安测试研究了NiCo_2S_4薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo_2S_4薄膜首次循环过程中的组成与结构变化。恒流充放电测试结果显示NiCo_2S_4薄膜在3μA·cm-2的放电电流下,0~3 V(vs Li+/Li)范围内,薄膜的首次放电容量为698 m Ah·g^(-1),经过200次循环之后的放电容量为365 m Ah·g^(-1);在循环伏安测试中得到了分步反应的可逆氧化还原峰。TEM和SAED分析结果揭示了NiCo_2S_4薄膜与Li的电化学反应机理:首次放电过程中NiCo_2S_4与Li发生转化反应生成了Li_2S、Ni和Co,充电后生成了CoS和NiS复合薄膜。后续循环为CoS和NiS复合薄膜的可逆分解与形成。研究表明NiCo_2S_4是一种有潜在应用价值的锂离子电池负极材料。展开更多
文摘先对炭纤维布(CC)进行不同时间的硝酸热处理,随后采用一步溶剂热方法在炭纤维布上沉积NiCo2S4纳米颗粒。结果表明,随着酸处理时间的延长,炭纤维表面粗糙度增加,含氧量增加。当酸处理时间为12 h时,NiCo2S4在其表面负载最均匀,复合材料的电化学性能最优,在电流密度为1 A g-1时,比容量可达1 298 F g-1,当增大到20 A g-1时,容量仍可保持为原来的89.7%。在5 A g-1电流密度下,循环次数达到3 000次时,容量保持率为95.3%。将所得复合材料作为正极,纳米炭纤维布(CNF)为负极,组装成具有自支撑结构的非对称超级电容器,在功率密度754 W kg-1时,其能量密度可达37.5 Wh kg-1。
基金jointly supported by the National Natural Science Foundations of China(No.51572246)the Fundamental Research Funds for the Central Universities(Nos.2652017401 and 2652015425)
文摘Bimetallic Ni–Co sulfides are outstanding pseudocapacitive materials with high electrochemical activity and excellent energy storage performance as electrodes for high-performance supercapacitors.In this study,a novel urchin-like NiCo2S4@mesocarbon microbead(NCS@MCMB) composite with a core–shell structure was prepared by a facile two-step hydrothermal method.The highly conductive MCMBs offered abundant adsorption sites for the growth of NCS nanoneedles,which allowed each nanoneedle to fully unfold without aggregation,resulting in improved NCS utilization and efficient electron/ion transferin the electrolyte.When applied as an electrode material for supercapacitors,the composite exhibited a maximum specific capacitance of 936 Fg-1 at 1 Ag-1 and a capacitance retention of 94% after 3000 cycles at 5 Ag-1,because of the synergistic effect of MCMB and NCS.Moreover,we fabricated an asymmetric supercapacitor based on the NCS@MCMB composite,which exhibited enlarged voltage windows and could power a light-emitting diode device for several minutes,further demonstrating the exceptional electrochemical performance of the NCS@MCMB composite.
基金the financial support of this study by the Ph.D.Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(grant number GK6530260034)the National Natural Science Foundation of China(grant numbers:51572052)。
文摘Urea oxidation is a significant reaction for utilizing urea-rich wastewater or human urine as sustainable power sources which can ease the water eutrophication while generate electricity. A direct urea-hydrogen peroxide fuel cell is a new kind of fuel cell employing urea as fuel and hydrogen peroxide as oxidant which possesses a larger cell voltage. Herein, this work tries to promote the kinetics process of urea oxidation by preparing low-cost and high-efficient NiCo2S4 nanowires modified carbon sponge electrode. The carbon sponge used in this work with a similar three-dimensional multi-channel structure to Ni foam, is prepared by carbonizing recycled polyurethane sponge which is also a process of recycling waste. The performance of the prepared catalyst in an alkaline solution is investigated in a three-electrode system.With the introduction of Co element to the catalyst, a reduced initial urea oxidation potential and a high performance are obtained. Furthermore, a direct urea-hydrogen peroxide fuel cell is assembled using the NiCo2S4 nanowires modified carbon sponge anode. Results indicate that the prepared catalyst provides a chance to solve the current problems that hinder the development of urea electrooxidation(high initial urea oxidation potential, low performance, and high electrode costs).
基金financially supported by the National Natural Science Foundation of China(21663029,21461024,21301147,21661029)the Guangdong Introducing Innovative and Enterpreneurial Team(2016ZT06C412)the Guangdong University of Technology Hundred Talents Program(220418136)
文摘Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Polyethylene glycol (PEG) 200 and thiourea were used as a shape-control age nt and sulfur source for in-s让u sulfuration, respectively. The urchin-like NiC02S4 was characterized by X-ray powder diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and electrochemical measurements. The resulting NiCo2S4 with ion diffusion-favored structure demonstrated remarkable electrochemical characteristics for supercapacitor with a high specific capacitance (1334F/g at 0.5 A/g) and superior rate capability (78.1% of the original capacity from 0.5 to 20 A/g) in 6M KOH aqueous solution. Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4 as a positive electrode and activated carb on (AC) as a n egative electrode. A NiCo2Sj/AC device exhibited a high energy density of 37.32 Wh/kg at a power density of 317.8 W/kg with capacity retention of 91.9% and up to 2000 charge/discharge cycles at 3 A/g. The results demonstrate that the sea-urchin-like NiCo2S4 has potential applications in supercapacitors.
文摘采用脉冲激光沉积法制备了NiCo_2S_4薄膜,利用恒流充放电和循环伏安测试研究了NiCo_2S_4薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo_2S_4薄膜首次循环过程中的组成与结构变化。恒流充放电测试结果显示NiCo_2S_4薄膜在3μA·cm-2的放电电流下,0~3 V(vs Li+/Li)范围内,薄膜的首次放电容量为698 m Ah·g^(-1),经过200次循环之后的放电容量为365 m Ah·g^(-1);在循环伏安测试中得到了分步反应的可逆氧化还原峰。TEM和SAED分析结果揭示了NiCo_2S_4薄膜与Li的电化学反应机理:首次放电过程中NiCo_2S_4与Li发生转化反应生成了Li_2S、Ni和Co,充电后生成了CoS和NiS复合薄膜。后续循环为CoS和NiS复合薄膜的可逆分解与形成。研究表明NiCo_2S_4是一种有潜在应用价值的锂离子电池负极材料。
