Gaire Madhu, Subedi Binod, Adireddy Shiva, Chrisey Douglas
Tulane University, Physics and Engineering Physics, School of Science and Engineering 6400, Freret St 2001 Percival Stern Hall New Orleans Louisiana 70118 USA
RSC Adv. 2020 Nov 4;10(66):40234-40243. doi: 10.1039/d0ra08510c. eCollection 2020 Nov 2.
We report a novel photonic processing technique as a next-generation cost-effective technique to instantaneously synthesize nanostructured manganese-cobalt mixed oxide reduced graphitic oxide (Mn-Co-rGO) for supercapacitor electrodes in energy storage applications. The active material was prepared directly on highly conductive Pt-Si substrate, eliminating the need for a binder. Surface morphological analysis showed that the as-prepared electrodes have a highly porous and resilient nanostructure that facilitates the ion/electron movement during faradaic redox reactions and buffers the volume changes during charge-discharge processes, leading to the improved structural integrity of the electrode. The presence of distinct redox peaks, due to faradaic redox reactions, at all scan rates in the cyclic voltammetry (CV) curves and non-linear nature of the charge-discharge curves suggest the pseudocapacitive charge storage mechanism of the electrode. The electrochemical stability and the life cycle were examined by carrying out galvanostatic charge-discharge (GCD) measurements at 0.40 mA cm constant areal current density for 80 000 cycles, and the electrode showed 95% specific capacitance retention, exhibiting excellent electrochemical stability and an ultra-long cycle life. Such remarkable electrochemical performance could be attributed to the enhanced conductivity of the electrode, the synergistic effect of metal ions with rGO, and the highly porous morphology, which provides large specific surface area for electrode/electrolyte interaction and facilitates the ion transfer.
我们报道了一种新型光子处理技术，作为一种具有成本效益的下一代技术，可即时合成用于储能应用中超级电容器电极的纳米结构锰钴混合氧化物还原氧化石墨烯（Mn-Co-rGO）。活性材料直接在高导电性的Pt-Si衬底上制备，无需使用粘合剂。表面形态分析表明，所制备的电极具有高度多孔且有弹性的纳米结构，这有利于在法拉第氧化还原反应过程中离子/电子的移动，并缓冲充放电过程中的体积变化，从而提高电极的结构完整性。循环伏安（CV）曲线在所有扫描速率下由于法拉第氧化还原反应而出现明显的氧化还原峰，以及充放电曲线的非线性性质表明该电极具有赝电容电荷存储机制。通过在0.40 mA cm的恒定面电流密度下进行恒电流充放电（GCD）测量80000次循环来检测电化学稳定性和生命周期，该电极显示出95%的比电容保持率，表现出优异的电化学稳定性和超长的循环寿命。这种卓越的电化学性能可归因于电极导电性的增强、金属离子与rGO的协同效应以及高度多孔的形态，后者为电极/电解质相互作用提供了大的比表面积并促进了离子转移。
