Abstract:

We used cyclic voltammetry to study the electrocatalytic behavior of binuclear Co-Mn phthalocyanine to determine whether binuclear phthalocyanine compounds have better electrocatalytic performance for the reduction of thionyl chloride than the mononuclear phthalocyanine compounds, cobalt phthalocyanine and iron phthalocyanine. Experiments were conducted in 1.5 mol·L-1 LiAlCl4/SOCl2 electrolyte solution and kinetic parameters were calculated to assess the electrocatalytic performance of the planar binuclear Co-Mn. Cyclic voltammograms showed that by comparison to the mononuclear cobalt phthalocyanine and iron phthalocyanine, the binuclear Co-Mn phthalocyanine had better catalytic activity for the reduction of thionyl chloride. The binuclear Co-Mn phthalocyanine increases the SOCl2 reduction potential and current by improving the exchange rate constant of SOCl2 reduction and the diffusion coefficient of SOCl2 on a glassy carbon electrode. Constant-current (10 mA) discharge curves of real ER14250-type Li/SOCl2 cells demonstrated that the binuclear Co-Mn phthalocyanine catalyst, which has better electrocatalytic activity than the mononuclear cobalt phthalocyanine and iron phthalocyanine, can increase the mid-point voltage to 0.3 V at low temperature (-30 ℃) and improve the discharge capacity to about 100 mAh at roomtemperature (25 ℃).

Key words: Electrocatalysis, Li/SOCl2 battery, Thionyl chloride, Binuclear Co-Mn phthalocyanine compound