Metal-organic framework-derived N, Zn-doped carbon materials loaded with PbO for suppressing hydrogen evolution and irreversible sulfation in lead-carbon batteries

Abstract

As an emerging electrochemical energy storage battery, lead-carbon batteries (LCBs) are characterized by with high safety, low cost, and long cycle life. However, due to the LCBs under high-rate partial state of charge (HPRSoC) conditions for a long time will lead to the phenomena of hydrogen evolution reaction (HER) and irreversible sulfation at the negative electrode, which seriously affects the performance of the batteries. In this work, MOFs-derived N, Zn-doped carbon (ZNC_acid) modified with PbO (PbO@ZNC_acid) was synthesized and applied as a negative electrode additive in LCBs. The ZNC_acid substrate has microporous and mesoporous structure, which facilitates the diffusion of electrolyte. Among them, the doping of Zn can effectively suppress hydrogen evolution, while N doping will generate more defects and enhance the electronic conductivity. More importantly, the PbO particles loaded on the ZNC_acid substrate not only inhibit HER but also provide nucleation sites for PbSO₄ crystal growth while enhancing the affinity between the carbon material and the negative active material (NAM). Owing to the superior properties of the synthesized PbO@ZNC_acid material, the LCB incorporating this additive achieves a specific capacitance of 153.6 mAh·g⁻¹ — a 38.74 % increase compared to the Blank battery (110.7 mAh·g⁻¹).Under HRPSoC conditions, the cycle life of the modified-battery is 33,729 times, which is 5.68 times that of the Blank battery (5937 times). This work provides valuable references for the application of lead-carbon composites in LCBs.