Improved rate and cycling performance of FeF2-rGO hybrid cathode with poly (acrylic acid) binder for sodium ion batteries

FeF2@MHCS Cathodes with High Capacity and Fast Sodium Storage Based on Nanostructure Construction

“…The absence of the Fe peak in XRD patterns could possibly be due to the small crystal sizes of Fe particles. 23 Therefore, the electrochemical process consists of the conversion reaction (FeF 2 + 2Na + + 2e − ↔ 2NaF + Fe) and the disproportionation reaction (FeF 2 + Na + + e − ↔ 1/ 3Na 3 FeF 6 + 2/3Fe), 23,25 with theoretical capacities of 571 and 286 mA h g −1 , respectively. The volume changes are determined as 169 and 136% for the conversion and disproportionation reactions, respectively (Figure S9).…”

“…23 This electrochemical activation process can enlarge the contact area between the electrolyte and electrode materials as well as shorten the ion diffusion distance in active materials. 25 Besides, during the reaction, small Fe crystals are generated, which can increase the electronic conductivity of the electrode. 49,52 The increase of contact area with the electrolyte, decrease of ion diffusion distance, and enhancement of electronic conductivity would together promote the reaction, thus increasing the capacity.…”

“…24 Recently, we fabricated FeF 2 −rGO nanocomposites based on the poly-(acrylic acid) (PAA) binder with an excellent rate performance of 78 mA h g −1 at 10 A g −1 . 25 However, these materials lack 3D porous structures, which restrain the electrolyte and ion transport. On the other hand, preparation processes such as freeze drying consume high energy, limiting their large-scale applications.…”

“…Ma et al prepared FeF 3 –Fe–reduced graphene (rGO) in situ derived from FeF 2 –rGO nanocomposites with relevant capacities reaching 150 mA h g –1 at 0.05 A g –1 and 60 mA h g –1 at 2 A g –1 . Recently, we fabricated FeF 2 –rGO nanocomposites based on the poly­(acrylic acid) (PAA) binder with an excellent rate performance of 78 mA h g –1 at 10 A g –1 . However, these materials lack 3D porous structures, which restrain the electrolyte and ion transport.…”

Rational Design of a Trifunctional Binder for Hard Carbon Anodes Showing High Initial Coulombic Efficiency and Superior Rate Capability for Sodium‐Ion Batteries

“…[8,9] Based on the experience from LIBs, the utilization of binders in SIBs are concentrated on the exploitation of new-type binders that can suppress volume expansion of electrodes or directly using commercial poly(vinylidene fluoride) (PVDF) binder. [10][11][12][13][14][15][16] However, the experience cannot solve irreversible side reactions at the interface and slow Na + transport of HC anodes. The primary reason for the issues derives from the difference in the carbon anodes used in LIBs and SIBs.…”