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 PbSO 4 , byproduct of discharge process, should be achieved to suppress the failure process of the LABs. We prepare carbon-enriched lead–carbon composite (~ 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 PbSO 4 , thereby promoting formation and decomposition of PbSO 4 . 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. Graphical Abstract