This application provides a separator, an electrical apparatus containing such separator, and preparation methods thereof. The separator includes a coating layer containing an organic-inorganic hybrid composite compound and provides improved performance in a number of aspects, and the organic-inorganic hybrid composite compound is formed by periodically assembling, along at least one spatial direction, basic units expressed by formula I, Lx(MaCb)y.Az. This application further provides a battery and an electrical device containing such separator, preparation methods thereof, and an organic-inorganic hybrid composite compound for improving performance of a separator.