Microwave-assisted synthesis of highly uniform Prussian Blue@Carbon cathode materials for sodium-ion batteries

Abstract

Prussian blue (PB) and its analogues (PBAs) as cathode material for sodium-ion batteries suffer from poor cycling stability because of crystal defects and sluggish ion diffusion kinetics. Composite with carbon materials is an effective solution to alleviate this problem. However, this is typically achieved through simple physical mixing or encapsulation, which relies heavily on the compatibility between carbon and PB, often resulting in composites that are neither stable nor uniform. Herein, we have developed a facile strategy that utilizes microwave radiation to anchor PB onto the surface of polyvinylpyrrolidone (PVP) functionalized graphene oxide (GO-PVP) through stable, uniform covalent bonds via the amide groups in PVP, in order to obtain an excellent composite material with Prussian blue and carbon materials for sodium-ion batteries. The as-prepared composite materials exhibit lower content of crystallization water and higher crystal integrity, delivering a high initial specific capacity of 165.2 mAh g −1 at 1 C rate and maintaining a capacity of 120.1 mAh g −1 after 500 cycles. This composite approach offers novel insights into the creation of uniform and stable PB/carbon materials as the cathode of sodium-ion batteries. Morphological transformation and microscopic mechanism diagram of composite materials. • PVP functionalized graphene oxide was employed to guide the anchoring of PB. • Microwave radiation provides additional energy to polar reactant molecules. • PB@GO-PVP(MR) delivers a capacity of 165.2 mAh g −1 with high cycle stability.