Rice husk derived porous carbon/β-PbO₂ composites as positive additives for lead‑carbon batteries

The continuous improvement of negative electrode in lead‑carbon batteries (LCBs) renders the positive electrode a considerable obstacle in overall performances of LCBs. Rice husk derived porous carbon/β-PbO₂ (RHC/β-PbO₂) composite was synthesized and incorporated as positive additive to improve the utilization efficiency of positive active substances (PASs). The effects of RHC/β-PbO₂ additives on the substance conversion, crystalline size, and utilization efficiency of positive plates were investigated during the curing, formation, and cycling stages. The remarkable conductivity of porous RHC/β-PbO₂ composite provides an efficient conductive network, while the hydrophilicity regulates the local ion transfer environment, significantly accelerating electron/ion transfer within PASs. The highest initial discharge capacity of 3.31 Ah at 0.05C was achieved at 1.2 wt% RHC/β-PbO₂, representing 19.9 % promotion over the blank battery. Meanwhile, the LCBs could maintain a discharge capacity of 1.65 Ah on 1C and deliver a capacity retention ratio of 86.8 % after 200 cycles, demonstrating exceptional rate capability and cyclic durability. The comprehensive work proposes an alternative approach for developing powerful positive additives and promoting the substance transformation in LCBs.