Boron doped graphene nanosheets as negative electrode additive for high-performance lead-acid batteries and ultracapacitors

Sulfation at the negative electrode is one of the major failure modes of lead-acid batteries. To overcome the issues of sulfation, in this work we synthesize Boron doped graphene nanosheets as an efficient negative electrode additive for lead-acid batteries. 0.25wt % Boron doped graphene nanosheets additive in negative electrode which contains around 3% of Boron doping shows impressive electrochemical performance in first discharge capacity, similar to 60% increase the capacity in relation to the conventional lead-acid cell. Noticeably, 15-20% enhancement in the discharge capacity at lower C rates and almost double increase in capacity at higher C rates show Boron doped graphene nanosheets as a potential additive for lead-acid battery operating under high rate partial state of charge applications. The superior electrochemical performance is due to the p-type or hole conductivity of the Boron doped graphene lattice, which reduces lead sulfate formation and thereby enhances active material utilization, charge acceptance, and reduces hydrogen evolution. Besides, the high C-rate performance of Boron doped graphene nanosheets additive cell is due to the capacitive property of Boron-doped graphene nanosheets which delivers specific capacitance of 90 F g(-1) at 2 A g(-1) with > 75% capacity retention at the end of 2000 cycles. (C) 2019 Elsevier B.V. All rights reserved.