Rationalized Molten-Salt Synthesis of Carbon-Enriched Pb-C Composite for Lead-Acid Battery Positive Electrode Grids

Enhancement of cycle retention and energy density is urgent and critical for the development of high-performance lead-acid batteries (LABs). Facile removal of PbSO4, byproduct of discharge process, should be achieved to suppress the failure process of the LABs. We prepare carbon-enriched lead-carbon composite (similar to 1.23 wt. % of carbon). The modified molten-salt method is applied to prepare the lead-carbon composite. Various synthetic parameters for the molten salt reaction such as a kind of salt, carbon sources, and sample-harvesting condition are investigated. Carbon does not participate in the redox reaction of Pb. However, carbon plays a pivotal role in reducing overpotential during redox reaction of PbSO4, thereby promoting formation and decomposition of PbSO4. Also, we firstly show that carbon inhibits hydrolysis followed by loss of the electrolyte. In addition, the carbon-enriched lead-carbon composite reveals the enhanced corrosion resistance compared with lead or other lead-carbon composites. Considering high electrochemical reversibility and corrosion resistance, the carbon-enriched lead-carbon composite is the promising current collector for the LAB system. We provide the rationalized design rule toward the carbon-enriched lead-carbon composite, which can make breakthrough over the conventional preparation route for lead-carbon composites. [GRAPHICS] .