A DFT study of H2 adsorption on Li-decorated C-doped BN nanochains

Abstract

By density functional theory (DFT), a new C-doped boron nitrogen nanochain with lithium decoration was designed for hydrogen storage. The lithium adsorption behavior of BN chains with different doping ratio and methods of carbon atoms was systematically studied. The results proved that the metal binding energy could be effectively improved after replacing the N atom in the pure BN chain with C. When a lithium atom was adsorbed, the metal binding energy of the B8N7C nanochain was the highest, reaching 3.79 eV, much higher than the cohesive energy of Li, which avoided lithium cohesion. When two lithium atoms were adsorbed, the metal binding energy of the B6N5C nanochain was the highest, reaching 2.67 eV. For carbon doping ratios of 6.11 %, 6.99 %, 8.18 %, 9.84 %, 12.35 % and 16.58 %, each lithium atom could adsorb almost four H2 molecules, and the average binding energy was about 0.14 eV. When the carbon doping ratio was 16.58 %, the maximum H2 mass ratio of 18.68 wt% was reached. These results all indicate that the Li-BCN series nanochains are a very promising hydrogen storage material.