Abstract
Charge‐discharge characteristics of 
secondary cells using 
melts and 
melts were investigated at various temperatures. Cyclic voltammetry and ac impedance measurements were performed by using planar 
and 
electrodes at 60–150°C in two kinds of the basic 
melts: BPC‐rich (17 mole percent (m/o) BPC) and BPC‐poor (7 m/o BPC) melt. The charge‐discharge characteristic dependence on temperature and melt composition was responsible not only for the change of the conductivity of the melt but also for the change of activation and diffusion processes for the electrochemical reactions which proceed on the 
electrode. The cathodic reaction in the BPC‐rich melt was controlled by the diffusion rather than the activation process, while the anodic reaction was under activation control. The activation energies for the anodic and the cathodic reaction below 140°C are 40 and 19 kJ/mol, respectively.