基于SWCNT复合硫化镍/氮化镍电极材料的制备及其电化学性能

Preparation and Electrochemical Properties of Composite Nickel Sulfide/Nickel Nitride Electrode Material Based on SWCNTs

以单壁碳纳米管(SWCNT)为碳源,氯化镍为金属源,硫脲为氮源和硫源,通过水热和高温热解方法制备N,S-Ni@S@C复合材料,并对复合材料进行物理表征和电化学性能测试。结果表明,SWCNT与硫化镍、氮化镍复合的结构不仅能提高电极材料的电导率,还能提供更多的活性位点供电解质离子插入或脱出,从而显著提高电化学性能。在三电极体系下,N,S-Ni@S@C复合材料具有较高的电压窗口(1.5 V)和优异的充放电能力,在电流密度为1 A·g^(-1)下,N,S-Ni@S@C的比电容可达162.45 F·g^(-1)。其比电容与SWCNT相比提高了2.61倍,与SWCNT和氯化镍复合材料(C@Ni)相比提高了19倍,与SWCNT和硫脲复合材料(C@S@N)相比提高了16倍。此外,以N,S-Ni@S@C复合材料为正极,商业活性炭(YP50F)为负极,组装得到非对称型超级电容器(N,S-Ni@S@C//AC)。该非对称型超级电容器在功率密度为818.78 W·kg^(-1)时,其能量密度可达41.03 W·h·kg^(-1),在电流密度为1.0 A·g^(-1)时,经过5000次连续充放电循环后比电容仍可保持初始比电容的82%。

N,S-Ni@S@C composites were prepared by hydrothermal and high temperature pyrolysis method with single-walled carbon nanotubes(SWCNTs)as carbon source,nickel chloride as metal source,thiourea as nitrogen source and sulfur source,and physical characterization and electrochemical property test of the composites were carried out.The results show that the composite structure of SWCNTs with nickel sulfide and nickel nitride can improve the conductivity of the electrode materials,and provide more active sites for the insertion or removal of electrolyte ions,thus significantly improving the electrochemical performance.In a three-electrode system,N,S-Ni@S@C composites have high voltage window(1.5 V)and excellent charge and discharge capability.At a current density of 1 A·g^(-1),the specific capacitance of N,S-Ni@S@C composites can reach 162.45 F·g^(-1).The specific capacitance is 2.61 times higher than that of SWCNTs,is 19 times higher than that of SWCNTs and nickel chloride composites(C@Ni),is 16 times higher than that of SWCNTs and thiourea composites(C@S@N).In addition,with N,S-Ni@S@C composites as the positive electrode and commercial activated carbon(YP50F)as the negative electrode,the asymmetric supercapacitor(N,S-Ni@S@C//AC)was assembled.The energy density of the asymmetric supercapacitor reaches 41.03 W·h·kg^(-1)at a power density of 818.78 W·kg^(-1).When the current density is 1.0 A·g^(-1),the specific capacitance can still maintain 82%of the initial specific capacitance after 5000 continuous charge and discharge cycles.