Preparation of g-C₃N₄/Pb composites and application in anode materials for lead carbon batteries

To improve the hydrogen precipitation defects and increase the cycle life of lead carbon batteries, layered graphite phase carbon nitride (g-C₃N₄) was prepared using urea as a precursor and used as an additive to prepare anode plates for lead carbon batteries. The effects of the structure and addition amount of g-C₃N₄ on the electrochemical performance of lead carbon batteries were investigated with activated carbon (AC) as the control. The results show that the hydrogen evolution reaction (HER) is significantly suppressed by the addition of g-C₃N₄, and the hydrogen precipitation current of 1wt%g-C₃N₄ negative plate at −1.5 V is only 6% of that of the activated carbon negative plate. The AC impedance spectra show impedances (R_s) of 0.19868 Ω and 1.749 Ω for 1wt%g-C₃N₄ and activated carbon anode materials. More importantly, the capacitance of 1wt%g-C₃N₄ negative electrode plate is 344% higher than that of 1wt%AC negative electrode plate. In the 5000 h high-rate partial-state-of-charge (HRPSoC) battery cycle life test, the addition of g-C₃N₄ improved the battery life by 62% compared to the addition of activated carbon. After 500 cycles, the battery capacity retention rate is still 70%. g-C₃N₄ can effectively inhibit the hydrogen precipitation reaction, increase the specific capacitance and thus extend the cycle life of the battery, and at low cost, can be used as a new anode additive to improve the performance of lead carbon batteries.