A Procedure for Evaluating the Capacity Associated with Battery-Type Electrode and Supercapacitor-Type One in Composite Electrodes

This paper provides a procedure for evaluating the capacity or charge of composites consisting of battery-type electrode and supercapacitor-type one. The composites, which are binder-free flexible materials, consist of cobalt oxide (CoOx) electrodeposited on the fibers of a carbon cloth (CC). The deposited CoOx shows battery-type response. The CC substrate shows supercapacitor-type one. The procedure here reported is based on galvanostatic charge/discharge measurements. It is easier, less laborious and faster than the procedure based on the kinetic study by cyclic voltammetry. The two procedures are compared. The dependences of the specific capacities as functions of the current density and voltage scan rate show similar patterns. The contribution of the two types of materials to the specific capacity of the complete electrode is discussed. The electrodedeposited CoOx contributes increasing the specific capacity of the composites at low current densities. The CC substrate dominates the specific capacity of the composites at high current densities.Financial support through the project FCT-M-ERA-NET/0004/2014- PCIN2015-024 is gratefully acknowledged. Authors thank Prof. G. Z. Chen from the University of Nottingham (UK) for helpful discussions. We also thank J. A. Diaz from Carbongen SA, and R. Beneito and J. Vilaplana from AIJU for providing the bare carbon clothPeer Reviewe