Effects of BTA and TBAB electrolyte additives on the properties of zinc electrodes in zinc–air batteries

In order to improve the performance of zinc–air batteries, the effects of addition amounts of single Benzotriazole (BTA), Tetrabutylammonium bromide (TBAB) and their compounds on the electrochemical performance of the zinc electrodes were studied. In addition, the mechanisms of the hydrogen evolution inhibition, the dendrite suppression and the passivation improvement were investigated. The results showed that the addition of BTA, TBAB or the combination of both to the alkaline electrolyte were all beneficial for inhibiting the hydrogen evolution and corrosion, suppressing the dendrites and delaying the passivation. When BTA and TBAB were added alone, the optimal amounts were 100 mg/L and 200 mg/L, respectively. It was found that the hydrogen evolution inhibition effect of BTA was better than that of TBAB, while the effect of TBAB on suppressing the zinc dendrite was better than BTA. When BTA and TBAB were added together, the optimal amount was 100 mg/L BTA + 50 mg/L TBAB. Under this condition, the hydrogen evolution and corrosion inhibition efficiency was increased from 48.5 to 61.4% when 100 mg/L BTA was added alone. The specific capacity of the zinc–air battery after 50th cycles was increased from 327.3 mAh/g without additives to 475.6 mAh/g, and the capacity retention rate after 50 cycles reached 83.2%.