Na-Rich Prussian White Cathodes for Long-Life Sodium-Ion Batteries

Abstract

Prussian blue analogues (PBA) recently have received great interest for promising applications in low-cost sodium-ion batteries (SIBs). However, controlled synthesis of high-performance PBA is still challenging. In this work, a facile precipitation route was used to synthesize Na-rich PBAs with superior electrochemical performance. It was found that two shapes of the products, namely, small irregular particles and large cuboid particles, coexist by adding sodium citrate in the sodium hexacyanoferrate side during the synthesis. The product shows large capacity (144 mAh g–1 under a 0.1 C rate), good rate performance (115.6 mAh g–1 under a 1 C rate, 86.6 mAh g–1 under a 10 C rate), and long-term cycling stability (73.4% retention after 780 cycles under a 0.5 C rate, 72.7% retention after 2100 cycles under a 1 C rate). This work offers a promising route to prepare PBA-based cathode materials for high-performance SIBs.

Constructing Na‐Ion Cathodes via Alkali‐Site Substitution

“…A long‐term cycling stability at 3 C is obtained in Figure 4d, which exhibits the capacity retention of >78% over 1800 cycles with a much smaller capacity decay of ≈0.012% per cycle. The comparison of long‐term cycling performance on the representative PBA Na‐ion cathodes, including vacuum‐dried Na 2 MnFe(CN) 6 , [ 18 ] high nickel gradient PB (HNGPB) Na 1.04 Fe 0.83 Ni 0.17 [Fe(CN) 6 ] 0.76 , [ 17a ] small irregular particles at size of 200–600 nm Na 1.80 Mn[Fe(CN) 6 ], [ 20 ] sodium citrate‐treated Na 1.87 Ni 0.05 Mn 0.95 [Fe(CN) 6 ] 0.98 , [ 21 ] high‐crystallinity Na 1.68 Ni 0.14 Co 0.86 [Fe(CN) 6 ] 0.84 , [ 19 ] CNT‐intertwined Na 2 Fe[Fe(CN) 6 ], [ 17b ] and Na 1.6 Fe 1/6 Mn 5/6 [Fe(CN) 6 ], [ 22 ] are shown in Figure a,b indicating an ultra‐stable capability of this present K‐stabilized [K 0.444(1) Na 1.414(1) ][Mn 3/4 Fe 5/4 ](CN) 6 cathode material.…”

“…Comparison of long‐term cycling performance on the representative Prussian blue analogs (PBA) Na‐ion cathodes of a) capacity retention and b) capacity decay per cycle, including this present K‐stabilized material, vacuum‐dried Na 2 MnFe(CN) 6 , [ 18 ] high nickel gradient Prussian blue (HNGPB) Na 1.04 Fe 0.83 Ni 0.17 [Fe(CN) 6 ] 0.76 , [ 17a ] small irregular particles (SIP) at size of 200–600 nm Na 1.80 Mn[Fe(CN) 6 ], [ 20 ] sodium citrate‐treated Na 1.87 Ni 0.05 Mn 0.95 [Fe(CN) 6 ] 0.98 , [ 21 ] high‐crystallinity Na 1.68 Ni 0.14 Co 0.86 [Fe(CN) 6 ] 0.84 , [ 19 ] and Na 1.6 Fe 1/6 Mn 5/6 [Fe(CN) 6 ]. [ 22 ] …”

Building High Power Density of Sodium-Ion Batteries: Importance of Multidimensional Diffusion Pathways in Cathode Materials

“…The valence of Fe is +2, however, and it is vulnerable to being oxidized to +3, so an inert atmosphere is required during both fabrication and centrifugal separation processes. By facile sodium citrate added precipitation method, Na-rich monoclinic phase Na x MnFe(CN) 6 was successfully synthesized by Shen et al (2018). Uniform microsize cuboid particles were obtained, and all the involved elements were uniformly distributed (Figures 2A-C).…”

“…(D) Charge-discharge profile and (E) C-rate performance of the as-obtained sample. Reproduced from paper (Shen et al, 2018) with permission from the American Chemical Society. Charge density analyses of (F) cubic-structured NiHCF and (G) rhombohedral-structured NiHCF.…”

Cathode material for sodium-ion batteries based on manganese hexacyanoferrate: the role of the binder component

“…Na 2 MnFe(CN) 6 was synthesized by a hydrothermal method, similar to described in [8]. Namely, 6 mmol of MnSO 4 was dissolved in 100 ml of water and added dropwise to a solution containing 3 mol of Na 4 [Fe(CN) 6 ], 12 mmol of sodium citrate, and 0.24 mol of NaCl in 100 ml of water.…”