Ball Milling-Enabled Fe^2.4+ to Fe³⁺ Redox Reaction in Prussian Blue Materials for Long-Life Aqueous Sodium-Ion Batteries

Abstract

Aqueous Na-ion batteries using Prussian blue materials have inherent advantages in safety, material sustainability, and economic cost. However, it is challenging to obtain long-term cycling stability because many redox reactions have poor intrinsic stability in water. Here, we demonstrate reversible Fe 2.4+ to Fe 3+ redox reaction of Prussian blue electrodes cycled in a 17 m NaClO 4 water-in-salt electrolyte. The cubic phase c-Na 1.17 Fe[Fe(CN) 6 ]•0.35H 2 O) derived from monoclinic Prussian blue (m-Na 1.88 Fe[Fe(CN) 6 ]•0.7H 2 O) through ball milling delivers excellent cycling stability of >18,000 cycles with >90% capacity retention at the 10C rate. The specific capacity is ∼75 and ∼67 mAh/g at 1C and 10C rates, respectively. Systematic characterizations including electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Xray absorption spectroscopy have verified the phase transition and iron oxidation state evolution, revealing the mechanism that enables the material's high rate and long durability as the battery cathode.

Solid-state synthesis of diminutively granular and highly crystalline manganese hexacyanoferrate for a supercapacitor electrode

“…This phenomenon is similar to a previous report. 27 The SAED pattern (Fig. 4B) exhibits a polycrystalline structure.…”

Electrochemically Active Mn2+ Enabling High-Performance Aqueous Zinc Ion Batteries

“…Figure 6a shows XRD pattern of cathodes after cycling in Zn 0.5 K 0.25 Mn 0.01 . The The pattern exhibits three sharp peaks at 16 While XRD pattern after cycling provides further understanding into the insertion/extraction process in MnO 2 . SEM of the cross-section electrode in Figure 6b reveals that the electrode is composed of carbon paper, KZnHCF and electrodeposition products.…”

Progress on Transition Metal Ions Dissolution Suppression Strategies in Prussian Blue Analogs for Aqueous Sodium-/Potassium-Ion Batteries

“…The development of composites based on PBAs presents a strategy for enhancing electrochemical attributes in ASIBs. For instance, Feng et al enhanced the specific capacity and rate performance of Na 1.88 Fe[Fe(CN) 6 ]·0.7H 2 O by integrating Ketjenblack through a ball milling process [ 123 ]. Similarly, Zarbin et al synthesized carbon nanotube composite PBAs, where the formation of PB on individual CNTs facilitated slower Fe diffusion, thereby improving reversibility and stability in APIBSs [ 124 ].…”