Abstract:

Using Robinia pseudoacacia branches as raw materials, the activation process of activated carbon with double-layer electrode was optimized by response surface method using water vapor activation method and the mass specific capacitance at current density of 1A/g as the index. The electrochemical properties of the prepared double-layer electrode Robinia pseudoacacia carbon were studied by constant current charge/discharge, cyclic voltammetry curve and AC impedance methods. The experimental results showed that the best process for preparing the double-layer electrode Robinia pseudoacacia charcoal was that the activation temperature of 1 g charcoal was 674.85 ℃, the activation time was 82.42 min, the water vapor flow rate was 0.92 g/min, and the specific capacitance predicted by the model was 133.2 F/g. The significance of the activation conditions on the specific capacitance of activated carbon was: activation temperature>water vapor flow rate>activation time. The double-layer electrode prepared under the optimized conditions had low resistance and strong conductivity. Its pore structure was conducive to the migration of ions on the electrode surface, and maintains good double-layer characteristics and magnification performance in the range of 10-50 mV/s.

Key words: locust branches, electrical double-layer electrode material, specific capacitance, response surface methodology