Proton transport mediated mesoporous SiO2 nanospheres for long-life lead-carbon battery

Abstract

The development of carbon-based negative additives in lead-carbon batteries (LCBs) renders the premature failure of positive electrode constrains further life improvement of LCBs. In this study, mesoporous SiO₂ nanospheres were prepared and incorporated into the positive electrode for promoting the cycling stability of LCBs. The action mechanism of SiO₂ nanospheres in the positive electrode of LCBs was investigated via exploring the initial discharge capacity, fast charging ability, rate capability, and cycling performance. Mesoporous SiO₂ nanospheres contribute to facilitate electrolyte penetration into the interior of positive active substances (PASs), while the hydroxyl groups on the surface and interior mesopores act as a proton reservoir, storing and releasing additional proton to promote the conversion kinetics of PbO₂/PbSO₄. Under the optimized content of 1.8 wt%, the highest initial discharge capacity of 3.36 Ah at 0.1 C and remarkable rate capability was achieved with a discharge capacity of 2.26 Ah at 1 C. Meanwhile, LCBs containing SiO₂ maintained a capacity retention ratio of 124.5 % after 120 cycles, delivering prominent cycling stability. These favorable properties can be attributed to the synergistic effect of the mesoporous structure and hydroxyl groups of SiO₂, which enhances the conversion rate of PASs and significantly improves the cycling stability.