Chen Tian, Li Songzhan, Gui Pengbin, Wen Jian, Fu Xuemei, Fang Guojia
Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan, 430072, People's Republic of China.
Nanotechnology. 2018 May 18;29(20):205401. doi: 10.1088/1361-6528/aab19b. Epub 2018 Feb 22.
Bifunctional bamboo-like CoSe arrays are synthesized by thermal annealing of Co(CO)OH grown on carbon cloth in Se atmosphere. The CoSe arrays obtained have excellent electrical conductivity, larger electrochemical active surface areas, and can directly serve as a binder-free electrode for supercapacitors and the oxygen evolution reaction (OER). When tested as a supercapacitor electrode, the CoSe delivers a higher specific capacitance (544.6 F g at current density of 1 mA cm) compared with CoO (308.2 F g) or CoO (201.4 F g). In addition, the CoSe electrode possesses excellent cycling stability. An asymmetric supercapacitor (ASC) is also assembled based on bamboo-like CoSe as a positive electrode and active carbon as a negative electrode in a 3.0 M KOH aqueous electrolyte. Owing to the unique stucture and good electrochemical performance of bamboo-like CoSe, the as-assembled ACS can achieve a maximum operating voltage window of 1.7 V, a high energy density of 20.2 Wh kg at a power density of 144.1 W kg, and an outstanding cyclic stability. As the catalyst for the OER, the CoSe exhibits a lower potential of 1.55 V (versus RHE) at current density of 10 mA cm, a smaller Tafel slope of 62.5 mV dec and an also outstanding stability.
通过在硒气氛中对生长在碳布上的氢氧化钴进行热退火合成了双功能竹状CoSe阵列。所获得的CoSe阵列具有优异的导电性、更大的电化学活性表面积，并且可以直接用作超级电容器和析氧反应（OER）的无粘结剂电极。当作为超级电容器电极进行测试时，与CoO（308.2 F/g）或CoO（201.4 F/g）相比，CoSe在电流密度为1 mA/cm时具有更高的比电容（544.6 F/g）。此外，CoSe电极具有优异的循环稳定性。还基于竹状CoSe作为正极和活性炭作为负极在3.0 M KOH水性电解质中组装了不对称超级电容器（ASC）。由于竹状CoSe独特的结构和良好的电化学性能，所组装的ACS可以实现1.7 V的最大工作电压窗口、在功率密度为144.1 W/kg时20.2 Wh/kg的高能量密度以及出色的循环稳定性。作为OER的催化剂，CoSe在电流密度为10 mA/cm时表现出1.55 V（相对于RHE）的较低过电位、62.5 mV/dec的较小塔菲尔斜率以及同样出色的稳定性。
