A STUDY OF RELAXATION PROCESSES IN LI-MNO2 CELLS

We analyze the decay of voltage V with time t after a current pulse has been applied to a LiMnO2 cell. We plot -tdV/dt and t2d2V/dt2 and show that we can resolve two distinct processes in the relaxation of the voltage. We show that the faster decay process is associated with diffusion in the electrolyte, both in the separators and in the pores of the cathode. The peak of the larger time constant appears to be associated with the cathode particles themselves. We calculate an upper bound for the diffusion constant of Li in MnO2 to be 6 × 10-12 cm2s-1.. © 1990.