Improving rechargeability of Prussian blue cathode by graphene as conductive agent for sodium ion batteries

Sodium ion batteries (NIBs) have gradually become an alternative to lithium ion batteries. Prussian blues (PBs) are regarded as a promising kind of cathode materials for NIBs, but their poor electrical conductivity has always been a considerable issue limiting its performance. In our work, we have optimized the PB cathode by utilizing reduced graphene oxide (RGO) as the conductive additive, whose performance is much higher than that of PB cathode with conventional conductive Super P. After optimization, our PB cathode with RGO additive delivers a reversible specific capacity of 80 mAh g-1 at 50 mA g-1 after 200 cycles without obvious attenuation. We also adopt current images and distribution of relaxation time technology to further analyze the reasons of electrochemical performance improvement. It is found that RGO conductive additive can remarkably enhance the intensity and uniformity of current in the electrode. We believe our work will provide new insights into the field of NIBs.