Self-Template Synthesis of Prussian Blue Analogue Hollow Polyhedrons as Superior Sodium Storage Cathodes

Abstract

Prussian blue and its analogues with three-dimensional frame structures have been shown to be of great importance in the research and development of sodium-ion batteries (SIBs). Herein, we develop a simple and convenient self-template method to prepare a hollow-structured Prussian blue analogue (CoFe-PBA). This structure is conducive to buffer the volume changes during ion extraction and insertion processes and shorten the ion diffusion path. When further building a thin polydopamine (PDA) coating, the synthesized CoFe-PBA@PDA exhibits a high discharge capacity of 123.1 mAh g −1 at 0.1 A g −1 with a capacity retention of 71.5% after 500 cycles. Moreover, the capacity retention of CoFe-PBA@PDA after 100 cycles is 14.3% higher than that of the two comparison samples. In addition, the reversible structure of CoFe-PBA@PDA without forming a new phase was verified by in situ X-ray diffraction. This work may provide another design idea or strategy for improving the stability of the PBA cathodes used in SIBs.

Interstitial Water Improves Structural Stability of Iron Hexacyanoferrate for High-Performance Sodium-Ion Batteries

“…The discharge capacity of HW-PB, MW-PB, and LW-PB is 117, 130, and 130 mAh g –1 , respectively. It is noteworthy that, for LW-PB and MW-PB, the capacity released at high voltage plateaus is higher than that of HW-PB, which can be speculated that the electrochemical activity of low-spin Fe III /Fe II increases with the removal of interstitial water …”

“…It is noteworthy that, for LW-PB and MW-PB, the capacity released at high voltage plateaus is higher than that of HW-PB, which can be speculated that the electrochemical activity of low-spin Fe III /Fe II increases with the removal of interstitial water. 41 The rate performances of HW-PB, MW-PB, and LW-PB were tested at different current densities; all of them exhibit excellent rate performances. HW-PB delivers specific capacities of 121.7, 117.…”

Vanadium‐based metal‐organic frameworks and their derivatives for electrochemical energy conversion and storage

“…197 Early work by Neff et al in the 1980s demonstrated the exceptional electrochemical activity and ionic permeability of Prussian blue crystals, which has led to the widespread use of PBAs in batteries to date. 198,199 Although the excellent crystal structure and simple diffusion kinetics of PBAs, the capacity delivered in aqueous systems has been limited to less than about 60 mA•h/g. The electrochemical process of PBAs is mainly controlled by the electrochemical process of metal ions inserting/extracting the ions.…”

“…The discovery of Prussian blue can be traced back to 1704 197 . Early work by Neff et al in the 1980s demonstrated the exceptional electrochemical activity and ionic permeability of Prussian blue crystals, which has led to the widespread use of PBAs in batteries to date 198,199 . Although the excellent crystal structure and simple diffusion kinetics of PBAs, the capacity delivered in aqueous systems has been limited to less than about 60 mA·h/g.…”

Amylopectin-Assisted Fabrication of In Situ Carbon-Coated Na3V2(PO4)2F3 Nanosheets for Ultra-Fast Sodium Storage

“…Among the various cathode materials like layered oxides, − Prussian blue analogues, , and organic cathodes, polyanions have been intensively investigated due to their 3D framework feature and a small volume change during sodium intercalation/deintercalation . Particularly, NASICON-type Na 3 V 2 (PO 4 ) 3 F 3 (NVPF) has been considered one of the most promising cathode materials for SIBs.…”