Thorn-like and dendrite lead sulfate as negative electrode materials for enhancing the cycle performance of lead-acid batteries

Abstract

During deep charge-discharge cycling of lead-acid batteries, the compact PbSO4 layer on the negative electrode surface blocks the ion transport channels, limiting the mass transfer process. In this study, to enhance the electrochemical characteristics of lead-acid batteries, thorn-like and dendrite PbSO4 with a high aspect ratio were prepared and used as negative electrode material. During the formation process, thorn-like and dendrite PbSO4 increased the pore diameter and the total pore volume of the negative electrode. For the charge-discharge process, this provided enhanced ion transport channels, which improved the utilization rate of the negative active material (NAM) and rate performance of batteries. Under a current density of 100 mA g−1 and 100% depth of discharge (DOD), the specific discharge capacity of thorn-like and dendrite PbSO4 batteries reached 110 mAh g−1, and the batteries still maintained >70% of the maximum specific capacity after 1200 cycles. When the capacity decayed to 80% of the maximum specific capacity, the cycle life of thorn-like and dendrite PbSO4 batteries was 64% higher than that of the nearly spherical PbSO4 batteries. Owing to the thorn-like and dendrite PbSO4 significantly changing the pore structure of the electrode and enhancing the mass transfer process, the irreversible sulfation of the negative electrode was inhibited, and the cycle life of the lead-acid battery effectively extended.