Capacitive contribution to lithium storage capacity in porous MoO ₃ films

Porous MoO₃ films are obtained by electrodepositing on Ni substrates. The galvanostatic charge/discharge tests show that, the film cathodes have a reversible capacity of 190 mA h g^-1 at a current density of 30 mA g^-1 between the voltage limits of 1.5-3.5 V vs. Li⁺/Li, a much better performance than the pristine MoO₃ powder. More than 75% capacitive contribution in the capacity of porous MoO ₃ films is responsible for the high capacity, according to the cyclic voltammetry analysis. Another improved property of the porous MoO₃ films is the rate performance, which still retains 70 mA h g^-1 at a current density of 1.25 A g^-1. The chronopotentiometry results reveal that, the prominent rate performances are owing to the high rate ability of the capacitive contribution.