▎ 摘　　要

NOVELTY - Composite material comprises alpha -lithium ferrous oxide nanocrystals and graphene; where the flaky graphene is used as a substrate, and the alpha -lithium ferrous oxide nanocrystals are dispersed on the graphene. USE - The composite material is useful for absorbing electromagnetic waves (claimed). DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the composite material, comprising (i) adding the graphite oxide into oleylamine, dispersing to obtain a first dispersion; (ii) adding iron acetylacetonate, lithium hydroxide monohydrate and octadecylamine into the first dispersion, forming a first mixture, under stirring heating the first mixture to a first predetermined temperature, performing first heat treatment, then continuing stirring, heating to a second predetermined temperature, carrying out second heat treatment to obtain a first reaction solution, and quenching the first reaction liquid; (iii) separating the first reaction solution to obtain alpha -lithium ferrous oxide nanocrystal-graphene composite first product, washing the first product, centrifuging and drying.