Ghani Faizan, Nah In Wook, Kim Hyung-Seok, Lim JongChoo, Marium Afifa, Ijaz Muhammad Fazal, Rana Abu Ul Hassan S
Department of Chemical Engineering, Dongguk University, 30, Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea.
Environment, Health, and Welfare Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea.
Nanomaterials (Basel). 2020 Nov 30;10(12):2389. doi: 10.3390/nano10122389.
Low-cost, vanadium-based mixed metal oxides mostly have a layered crystal structure with excellent kinetics for lithium-ion batteries, providing high energy density. The existence of multiple oxidation states and the coordination chemistry of vanadium require cost-effective, robust techniques to synthesize the scaling up of their morphology and surface properties. Hydrothermal synthesis is one of the most suitable techniques to achieve pure phase and multiple morphologies under various conditions of temperature and pressure. We attained a simple one-step hydrothermal approach to synthesize the reduced graphene oxide coated Nickel Vanadate (rGO@NiVO) composite with interconnected hollow microspheres. The self-assembly route produced microspheres, which were interconnected under hydrothermal treatment. Cyclic performance determined the initial discharge/charge capacities of 1209.76/839.85 mAh g at the current density of 200 mA g with a columbic efficiency of 69.42%, which improved to 99.64% after 100 cycles. High electrochemical performance was observed due to high surface area, the porous nature of the interconnected hollow microspheres, and rGO induction. These properties increased the contact area between electrode and electrolyte, the active surface of the electrodes, and enhanced electrolyte penetration, which improved Li-ion diffusivity and electronic conductivity.
低成本的钒基混合金属氧化物大多具有层状晶体结构，对锂离子电池具有优异的动力学性能，能提供高能量密度。钒的多种氧化态的存在及其配位化学要求采用经济高效、稳健的技术来扩大其形貌和表面性质的规模。水热合成是在各种温度和压力条件下实现纯相和多种形貌的最合适技术之一。我们获得了一种简单的一步水热法来合成具有相互连接的中空微球的还原氧化石墨烯包覆钒酸镍（rGO@NiVO）复合材料。自组装路线产生了微球，这些微球在水热处理下相互连接。循环性能表明，在200 mA g的电流密度下，初始放电/充电容量为1209.76/839.85 mAh g，库仑效率为69.42%，在100次循环后提高到99.64%。由于高表面积、相互连接的中空微球的多孔性质以及rGO的诱导作用，观察到了高电化学性能。这些特性增加了电极与电解质之间的接触面积、电极的活性表面，并增强了电解质的渗透，从而提高了锂离子扩散率和电子导电性。
