Electrochemical impedance studies of capacity fading of electrodeposited ZnO conversion anodes in Li-ion battery

Electrodeposited ZnO coatings suffer severe capacity fading when used as conversion anodes in sealed Li cells. Capacity fading is attributed to (i) the large charge transfer resistance, $$R_{\mathrm{ct}}$$ (300–700 $$\Omega $$ ) and (ii) the low $$\hbox {Li}⁺$$ ion diffusion coefficient, $$D_{\mathrm{Li}}⁺\ (10^-15$$ to $$10^-13\hbox { cm}²\hbox { s}^-1)$$ . The measured value of $$R_{\mathrm{ct}}$$ is nearly 10 times higher and $$D_{\mathrm{Li}}⁺$$ 10–100 times lower than the corresponding values for $$\hbox {Cu}₂\hbox {O}$$ , which delivers a stable reversible capacity.