Improved Li4Ti5O12 electrodes by modified current collector surface

A copper current collector is treated by electrolytic deposition of copper dendrites at the surface of the foil. This treatment results in a more structured surface leading to an improved contact between the electrode materials and the current collector. The contact to the electrode material particles of different sizes is investigated. Active materials of submicron size exhibit a drastically reduced internal resistance and a clearly improved C-rate capability. BET surface area measurement and calculation of roughness factor resulted in the finding of dendritic copper foil to provide an 8-fold larger surface area compared to the untreated foil. A comprehensive electrochemical impedance spectroscopy study is conducted for elucidation of electrochemical utilisation of the surface area increase. As a result, both fitting parameters for capacitance and surface resistance correspond to a similar normalization shift, indicating a clear improvement in the electro-active interface area. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

Treating a copper current collector through electrolytic deposition of copper dendrites can enhance the contact between electrode materials and the collector, especially improving performance for submicron-sized active materials. Dendritic copper foil provides an 8-fold larger surface area than untreated foil, leading to significant improvements in the electrochemical interface area.