Na-Based Electrodes for Electrochemical Cells

Introduction Because the low cost and abundance of sodium, there is a renewed interest in the development of Na-based electrodes, especially those that can be synthesized by hydrothermal method. Known for their excellent redox abilities and thermal stability, transition-metal polyphosphates have been studied in great detail [1]. Recently, Recham et al. [2] have shown the Na-cells with NaxFePO4F positive electrode display chargedischarge profiles in the 3-volt region. Brochu et al. have grown the NaFePO4 maricite phase by hydrothermal route [3]. In this work we present the insertion/extraction reaction of Na in/from FePO4.