Pseudocapacitors Go to Nanoscale for Performance Enhancement

Abstract

Nanotechnology can highly promote the electrochemical performances of transition metal oxide pseudocapacitors on the basis of thermodynamic data and kinetic reaction processes. The working mechanism of pseudocapacitors is fast and revisable surface Faradaic reactions on the electrodes which differ from bulk redox reactions in lithium ion batteries. The nanostructured electroactive materials with high specific surface areas, which can be efficiently contact with electrolyte, show enhanced power density. Meanwhile, the nanostructured materials can elevate the utilization ratio of electroactive materials and highly promote the energy density of pseudocapacitors. Besides, nanostructured materials can short the transport paths for ions of electrolyte and electrons in the electrode system, change electrode potential by modifying the chemical potentials of electrolyte ions and electrons for very small particles, and have more extensive solid solutions for ions intercalation, which benefit the high electrochemical performance.