Abstract:

Conversion anodes are attractive electrode materials for sodium-ion batteries due to their high theoretical and storage capacities. Challenges with conversion anode materials, such as metal phosphides, result from large volume expansion leading to anode pulverization, and poor reversible capacity. To improve the performance of metal phosphide anodes and relieve strain from volume expansion, preparation of composites and nanostructured materials provides a pathway to optimize anode performance. Zhang and coworkers evaluate the electrochemical performance of a series of bulk transition metal phosphides where the crystal structure of the bulk material is directly linked to the observed experimental capacity and electrochemical kinetics, with copper diphosphide (CuP₂) is identified as the optimal material. To further improve the electrochemical performance of CuP₂, the metal phosphide is encapsulated within a graphene network and the capacity is compared to the bulk materials and previously prepared CuP₂ composites. In this seminar, we will explore aspects of a battery electrochemical systems that contribute to the electrochemical performance and kinetic behaviors as well as evaluate the evidence provided in this work for the impact of crystal structure on anode performance