双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物（NCO）纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比，进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外，对NCO纳米片的电化学性能进行测试。结果表明，NCO-2（Ni_1.95Co₁O_x）纳米片在0.5 A·g^-1电流密度下，比电容为1 096.88 F·g^-1，且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器，在功率密度为576 W·kg^-1时，能量密度为57.70 Wh·kg^-1。

Dual-metal ions adjustable nickel and cobalt oxide nanosheets for asymmetric supercapacitors

A series of nickel and cobalt oxide (NCO) nanosheets were synthesized through a two-step hydrothermal-calcined method. Transition metal ions in NCO nanosheets were adjusted by changing the molar ratios of nickel and cobalt ions in precursor solutions. The crystalline phases, morphologies, and structures of the NCO nanosheets were characterized using X-ray diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. Furthermore, the electrochemical performances of the NCO nanosheets electrodes were tested. The result indicated that the NCO-2 (Ni_1.95Co₁O_x) nanosheets exhibited high specific capacitance of 1 096.88 F·g^-1 under 0.5 A·g^-1, which concurrently possessed a cycling ability of 78.26% after 5 000 cycles. Importantly, the asymmetric supercapacitor, which was constructed from the NCO-2 positive electrode and active carbon negative electrode, presented an energy density of 57.70 Wh·kg^-1 at a power density of 576 W·kg^-1.