The performance of energy storage and conversion devices is generally limited by their charge-storage mechanisms and materials, also determining their application fields. We believe that new energy materials can achieve unprecedented performance and unique behavior that existing devices cannot do are expected to resolve the technical limitations. In this regard, we are focusing on the following energy materials, including 2D nanomaterials, carbon nanomaterials, and polymeric and gel electrolytes, as well as their mechanistic studying through in situ/operando characterization as follows.