Electrochemical Study of Prussian White Cathodes with Glymes - Pathway to Graphite-Based Sodium-Ion Battery Full Cells

Abstract

Prussian white (PW) cathodes exhibit extremely fast rate kinetics for sodium ion (Na+) insertion/de-insertion at relatively high potentials. However, one of the major bottlenecks is to pair them with appropriate anode materials having similar rate kinetics. Herein, the combination of graphite anodes and several glyme-based electrolytes as appropriate building blocks for PW cathodes to achieve high power density without compromising on energy density is reported. Low defect, Na-rich PW is synthesized, and its electrochemical behavior is studied with conventional carbonate-based electrolytes as well as with diglyme (2G), tetraglyme (4G) and a 1:1 mixture of 2G and 4G. The stability of the electrolytes is also monitored via in situ (operando) pressure cell measurements. Graphite I electrolyte I PW cells are then studied in both two and three electrode configurations. It was found that glymes are compatible with the graphite/PW electrode pair and the resulting cells exhibit very good cyclability and rate capability.