Mo Tangming, Peng Jiaxing, Dai Wenlei, Chen Ming, Presser Volker, Feng Guang
School of Mechanical Engineering, Guangxi University, Nanning, Guangxi 530004, China.
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China.
ACS Nano. 2023 Aug 8;17(15):14974-14980. doi: 10.1021/acsnano.3c03886. Epub 2023 Jul 27.
Optimizing the synergy between nanoporous carbons and ionic liquids can significantly enhance the energy density of supercapacitors. The highest energy density has been obtained as the size of porous carbon matches the size of ionic liquids, while it may result in slower charging dynamics and thus reduce the power density. Enhancing energy storage without retarding charging dynamics remains challenging. Herein, we designed porous electrodes by introducing an optimized horn-like entrance to the nanopore, which can concurrently improve supercapacitors' charging dynamics and energy storage. Our results revealed the mechanism of improved charging lies in the gradual desolvation process and optimized ion motion paths: the former expedites the adsorption of the counterion by reducing the transitional energy barrier for ions entering the pores, and the latter accelerates the co-ion desorption and eliminates ion overfilling. Meanwhile, the enhancement of energy density could be attributed to the multi-ion coordinated migration.
优化纳米多孔碳与离子液体之间的协同作用可显著提高超级电容器的能量密度。当多孔碳的尺寸与离子液体的尺寸相匹配时,可获得最高能量密度,但这可能会导致充电动力学变慢,从而降低功率密度。在不阻碍充电动力学的情况下提高能量存储仍然具有挑战性。在此,我们通过在纳米孔中引入优化的喇叭状入口来设计多孔电极,这可以同时改善超级电容器的充电动力学和能量存储。我们的结果表明,充电改善的机制在于逐步去溶剂化过程和优化的离子运动路径:前者通过降低离子进入孔隙的过渡能垒来加速反离子的吸附,后者加速同离子解吸并消除离子过度填充。同时,能量密度的提高可归因于多离子协同迁移。