Hierarchical Porous Carbon Nanocomposites for Electrochemical Energy Storage

Hierarchically structured porous materials-and in particular hierarchically porous carbon composites-have had a major impact on the field of energy storage. Such composites can achieve high electrochemically active surface area, ion diffusion, electrical conductivity, and mechanical stability by tuning porosity, particle size, and morphology, all of which are critical to achieving high-performing energy storage materials. In this text, we will discuss the key factors affecting the performance of hierarchically porous carbon composites, primarily with regard to pore structure, explore means of synthesizing these composites, including hard and soft templating methods, aerogel formation, and self-assembly of pre-existing particles, and present some striking examples of the effect these composites can have on electrochemical energy storage performance, including their use both in conventional lithium-ion batteries and supercapacitors and in emerging technologies (e.g., lithium-sulfur battery cathodes and silicon anodes). As the material presented here shows, not only are these materials having a major effect on current energy storage research and technology, but a great deal of their potential has yet to be realized. We hope that this review will provide a solid foundation for those interested in the development of innovative and complex porous architectures for high-performance energy storage devices.