Insertion reaction of V₆O₁₃ electrodes reversibly incorporating divalent cations

Single crystal V₆O₁₃ has been evaluated for the insertion of divalent Zn and Cu ions. Coulometric studies have shown that V₆O₁₃ is reversible to both types of cation. A single-phase region exists in the range 0≤x≤0.14forZn_xV₆O₁₃ and 0≤x≤0.11forCu_xV₆O₁₃. Impedance and galvanostatic relaxation have both revealed that the diffusion coefficients of the divalent cations were of the order of 10^-10 cm²/s in the low concentration, single-phase regions. Diffusion rates were significantly reduced at higher concentrations. Impedance measurements have also shown that the kinetics of charge injection dominates the high freqeuncy response for both cations.