Prussian blue/reduced graphene oxide composites cathode material via one-pot precipitation synthesis for enhancing capacity sodium metal pouch cell batteries

Abstract

The popularity of sodium metal-ion batteries (SMBs) is increasingly displacing lithium-ion batteries (LIBs). Iron-based Prussian blue (Fe₄[Fe(CN)₆]₃) analogs promise low-cost and easily prepared cathode materials for sodium metal-ion batteries. However, the effectiveness of these materials has consistently been attributed to their inadequate electrical conductivity. In this study, we employed a one-pot synthesis technique to prepare composites of Prussian blue (PB) and reduced graphene oxide (PB/rGO) with varying rGO concentrations. Ascorbic acid was utilized as a reducing agent to convert graphene oxide (GO) into reduced graphene oxide (rGO). Following optimization, the SMB coin cell with PB/rGO(5 %) electrode exhibited an initial specific discharge capacity of 91 mAh/g at a current density of 0.3C. This electrode had exceptional rate performance and remarkable capacity retention, with 75.3 % remaining after 2000 cycles. Furthermore, the pouch cell SMB using PB/rGO(5 %) showed a high capacity of 87 mAh/g at 0.05C with an energy density of 34 Wh kg⁻¹ and good cycle ability over 500 cycles. Notably, the performance of the SMBs surpasses that of the PB cathode, making it highly advantageous for efficient sodium ion storage in SMBs.