Phosphate Electrolyte Design for Highly Reversible Sodium Ion Batteries

Sodium ion battery (NIB) is a very promising technology for the next generation of energy storage systems because of the abundance and low cost of Na in the Earth’s crust. However, the large-scale application of NIBs is still a challenge because of limited cycle life and potential safety concerns. In this regard, electrolyte plays a critical role in both cycle life and safety of NIBs. The battery stability is directly related to the properties of the electrode-electrolyte interphase. Therefore, designing advanced electrolytes with a stable electrode-electrolyte interphase is crucial to develop stable NIBs for their practical applications in large-scale energy storage. In this work, we report a phosphate-based electrolyte for sodium ion batteries with high capacity retention and excellent coulombic efficiency (99.9 %) during long term cycling. The details together with postmortem analysis of the cycled electrode will be discussed at the presentation. The insights obtained in this work can be used to further improve cycling stability and safety of rechargeable batteries.