Finding Harmony between Ions and Electrons: New Tools and Concepts for Emerging Energy Storage Materials

The study of charge transport within and between materials, including interfaces, is one of the most critical challenges facing electrochemistry due to its importance in determining rate and charge capacity in battery materials. In this perspective, we discuss examples of materials that reveal the delicate balance between structure, ion and electron transport, and chemically specific interactions that modulate reactivity during charge storage. We first address a new type of highly soluble redox-active polymers in which physical and electronic structure as well as interactions with the electrolyte determine their reaction mechanisms. Finding common ground with a variety of polymeric and 2D materials, we highlight new directions and strategies for enhancing electrochemical performance. Because of the importance in determining ion transfer mechanisms, we further explore ionically sensitive scanned probe methods that are helping to elucidate relationships between ion and redox reactivity. Examples of how these techniques are applied to ultrathin anodes and interfaces for ion batteries further underscore the importance of exploring the role of ion transfer and ionic interactions in emerging electrode materials. We hope that this perspective will provide new ways of approaching longstanding challenges in the field and provide key examples that encourage new directions in our understanding and control of the reactivity of energy storage materials.