Fabrication of ZnCoS nanomaterial for high energy flexible asymmetric supercapacitors
Fabrication of ZnCoS nanomaterial for high energy flexible asymmetric supercapacitors
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DOI：
10.1016/j.cej.2019.05.181
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发表时间：
2019-10
影响因子：
15.1
通讯作者：
Y. Zhang;N. Cao;S. Szunerits;A. Addad;P. Roussel;R. Boukherroub
中科院分区：
文献类型：
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作者：
Y. Zhang;N. Cao;S. Szunerits;A. Addad;P. Roussel;R. Boukherroub
与单金属硫化物相比，双金属硫化物作为负极材料具有更好的电化学活性，引起了人们的广泛关注。本文采用化学沉淀法和离子交换法合成了硫化锌纳米材料。所得的ZnCoS可以认为是由Co2+和Co3+部分取代了ZnS晶格中的Co2+的产物。从协同效应的角度出发，对硫化锌作为超级电容器电极材料进行了评价。通过改变制备条件，发现在50 °C下，以Co/Zn = 2的初始摩尔比合成的材料性能最好，最大比电容达到1134.7 F g−1 at 1 A g−1，约为裸电极材料的7.7倍。此外，该电极材料表现出良好的倍率性能(1~20 A g−1保持率为81%)和良好的循环稳定性，经6000次充放电循环后，20 A g−1的比容没有明显下降。由硫化锌和多孔还原石墨烯氧化物组成的柔性不对称超级电容器，在10 −1，10 S−1，能量密度17.7 W h kg−1，功率密度435 W kg−1下，显示出最大比电容约90 F g−1。
Bimetal sulfides as anode electrode materials have attracted extensive attention owing to their superior electrochemical activity compared to their mono-metal sulfide counterparts. Herein, ZnCoS nanomaterial was synthesized by chemical precipitation and ion-exchange process. The obtained ZnCoS can be considered as the product of partial substitution of Zn2+by Co2+and/or Co3+ions in the ZnS lattice. Benefiting from the synergistic effects, the ZnCoS was evaluated as electrode material for supercapacitors. By varying the preparation conditions, we found that the ZnCoS material synthesized using an initial mole ratio of Co/Zn = 2 at 50 °C gave the best performance with a maximum specific capacitance of 1134.7 F g−1at 1 A g−1, which is about 7.7 times that of bare ZnS electrode material. Furthermore, this electrode material exhibits good rate capability (81% retention from 1 to 20 A g−1) and excellent cycling stability with no obvious specific capacitance decrease at 20 A g−1after 6000 charging-discharging cycles. A fabricated flexible asymmetric supercapacitor, consisting of ZnCoS and porous reduced graphene oxide, displays a maximum specific capacitance of about 90 F g−1at 10 mV s−1with an energy density of 17.7 W h kg−1at a power density of 435 W kg−1.