Tuning the electrochemical behavior of graphene oxide and reduced graphene oxide via doping hexagonal BN for high capacity negative electrodes for Li and Na ion batteries.

ABSTRACT

Inspired by the recently synthesized hexagonal boron nitride (h-BN) doped graphene, density functional theory (DFT) calculations were performed to evaluate the anodic properties of BN doped graphene (BN-G), graphene oxide (BN-GO) and reduced graphene oxide (BN-rGO) for Li/Na ion batteries (LIBs/NIBs). Our proposed materials show a semiconducting character with band gaps of 1.4, 0.67 and 0.45 eV for BN-G, BN-GO and BN-rGO, respectively. Among the three nanosheets, BN-rGO shows strong interaction behavior with Li/Na whereby the defected site exhibits high reactivity compared to the other adsorption sites. The adsorption energies are found to be about -4.72/-4.10 eV for Li/Na at the defected site, which are consecutively 3 and 2 times stronger than the adsorption energies of BN-G and BN-GO. It is predicted by partial density of states (PDOS) and band structure analysis that the nanosheets will exhibit metallic behavior through the adsorption process. Relatively low diffusion barriers are found to be about 0.47 and 0.22 eV when Li and Na moved from one adsorption site to another nearby adsorption site on BN-rGO. Among them, BN-rGO shows a high specific capacity, about 1583 and 1319 mA h g-1 for LIBs and NIBs. Therefore, the suitable adsorption energy with metallic behavior of the nanosheet combined with the high specific capacity confirm that BN-rGO is a promising anode candidate for Li/Na ion batteries.