Repairing vacancy defects for stabilization of high surface area hexagonal boron nitride under harsh conditions

•The vacancies-repaired Ni-h-BN-V exhibits high-temperature antioxidant stability.•The Ni2+ preferentially repairs B-vacancy rather than N-vacancy in defective h-BN.•The strong antioxidant stability is due to the weak oxygen affinity of Ni-h-BN-V.•Repairing the vacancies is an effective strategy for preparing few-layer h-BN-V.