2d van der Waal SiC/borophene heterostructure as a promising anode for high-capacity Li ion battery: First principles study

Abstract

We constructed SiC/borophene heterostructure based on the method of commensurate lattice with supercell approach and studied the structural, electronic and electrochemical properties using density functional theory (DFT). The interfacial binding energy of SiC/borophene is as high as −26.07 meV/Å2. Significant amounts of charge were found to drift from SiC to borophene, resulting in interfacial charge redistribution and increased Li binding affinity on the surfaces. The electronic properties of SiC/borophene showed pronounced metallic conductivity, a trait conducive to anodic applications in electrochemical cells. The calculated Li adsorption energy at the interface of SiC/borophene is −2.23 eV. Multiple layer adsorption is also observed, with the heterostructure retaining much of its structural integrity after adatom adsorption, indicating possible good cycling stability. At the maximum concentration, the Li storage capacity for SiC/borophene is 1980.63 mAh/g, surpassing a large variety of other reported 2D complexes. Also, an overall average operating voltage of 1.06 V is maintained in the structure, which is in proximity of the optimal 1.5 V threshold requisite for anodic operations. The diffusion energy barriers associated with lithium ion migration across the three distinct adsorption sites of the heterostructure all reveal a nominal magnitude with the lowest barrier energy of 0.54 eV at the top of borophene adsorption layer and site. These findings show that SiC/borophene could be used as an anode in very high-capacity lithium-ion batteries.