A Chemical Precipitation Method Preparing Hollow–Core–Shell Heterostructures Based on the Prussian Blue Analogs as Cathode for Sodium‐Ion Batteries

Abstract

Prussian blue and its analogs are regarded as the promising cathodes for sodium-ion batteries (SIBs). Recently, various special structures are constructed to improve the electrochemical properties of these materials. In this study, a novel architecture of Prussian blue analogs with large cavity and multilayer shells is investigated as cathode material for SIBs. Because the hollow structure can relieve volume expansion and core-shell heterostructure can optimize interfacial properties, the complex structure materials exhibited a highly initial capacity of 123 mA h g and a long cycle life. After 600 cycles, the reversible capacity of the electrode still maintains at 102 mA h g without significant voltage decay, indicating a superior structure stability and sodium storage kinetics. Even at high current density of 3200 mA g , the electrode still delivers a considerable capacity above 52 mA h g . According to the electrochemical analysis and ex-situ measurements, it can be inferred that the enhanced apparent diffusion coefficient and improved insertion/extraction performance of electrode have been obtained by building this new morphology.

A Heterostructure Coupling of Bioinspired, Adhesive Polydopamine, and Porous Prussian Blue Nanocubics as Cathode for High‐Performance Sodium‐Ion Battery

“…Herein, sodium citrate as chelating agent can form a stable complex with Fe ions through coordination interaction, which can slow down the nucleation and subsequent crystal growth, discrete phase may be obtained at a high temperature and thus porous PB is achieved. [ 40–41 ] Moreover, sodium citrate as the buffering agent can adjust the pH value to fabricate porous PB. [ 42–44 ] Subsequently, polydopamine was spontaneously polymerized onto the porous NFF surface after adding dopamine acid solution via a self‐polymerization process, and the as‐obtained product was denoted as porous NFF@PDA.…”

Hierarchical Hollow Prussian Blue Rods Synthesized via Self‐Sacrifice Template as Cathode for High Performance Sodium Ion Battery

“…As shown in SEM images (Figure ), R‐PB possessed a unique hierarchical hollow rod structure, which was proposed to promote the fast diffusion of Na + . This was supported by the CVs with different scan rates.…”

“…Yue et al developed a facile template‐free solution approach to synthesize a mesoporous PBA (NiHCF/t) with a capacity of 65 mAh g −1 at low current density. PBAs with mesocrystalline structure, nanoframes structure, and hollow core–shell heterostructure were reported as well. These special structures and the corresponding large surface areas were retained during the charge–discharge process, leading to their high capacities and/or stabilities.…”

“…The stoichiometry of prussian blue (PB) and its analogues (PBAs) is represented by the general chemical formula A x M 1 [M 2 (CN) 6 ] y ⋅□ 1− y ⋅ n H 2 O (where A = alkaline metal ions; M 1 and M 2 = transition metal ions; □ = [M(CN) 6 ] vacancies occupied by six‐fold coordinated water; 0 < x < 2; y < 1) . The electrochemical performances of PBAs as cathodes for SIBs depend on the types of transition metals ions (M 1 and M 2 ), number of vacancies (1 − y ), and content of coordinated water ( n ) . Among various transition metal ions in PBAs, Mn‐based PBA (PBM) delivers superior electrochemical activity, but inferior stability .…”

Hollow structured cathode materials for rechargeable batteries

“…10b). Huang et al [128] prepared a hollow core-shell Na 2 Mn x Ni y Fe(CN) 6 heterostructures by simple chemical precipitation as superior cathode materials for SIBs (Fig. 10c) .…”