Fluoro(Phosphates,Sulfates) or (Phosphate,Sulfate) Fluorides: Why Does It Matter?

Abstract

Phosphate (sulfate) fluorides have attracted much attention recently as potential positive electrode materials for rechargeable batteries. However, they are broadly referred to fluorophosphates and fluorosulfates by the community. This nomenclature inaccuracy is probably lowering the visibility of papers dealing with “true” fluorophosphates/fluorosulfates and may lead to some confusion about the structural peculiarities of both families of compounds.

Conversion of Amorphous MOF Microspheres into a Nickel Phosphate Battery-Type Electrode Using the “Anticollapse” Two-Step Strategy

“…Porous transition metal phosphates have been recently investigated as ideal candidate electrode materials for supercapacitors due to their outstanding electrochemical performances, abundant reserves, nontoxicity, and low costs. − Pang and co-authors successfully synthesized ultrathin cobalt–nickel phosphate nanosheets that exhibited a capacity of 453 C g –1 at a current density of 1 A g –1 . The amorphous cobalt hydrogen phosphate nanosheets prepared by Lu et al display a high capacity of 164.48 C g –1 and excellent stability .…”

KFe(C2O4)F: A Fluoro‐oxalate Cathode Material for Li/Na‐Ion Batteries

“…[4f] Combining different anion sublattices in a polyanionic system in which the crystal structure was varied with different chemical composition has been found to offer tunable electrochemical activity. [5] Incorporation of fluorine is expected to increase the operating potential due to the higher ionicity of the metal-fluoride bond, resulting in higher energy density. Bearing these considerations in mind, researchers have synthesized various electrochemically active phosphate and sulfate-based mixed metal fluoride compounds such as AVPO 4 F (A = Li, Na, K), [6a] Na 3 V 2 O 2 (PO 4 ) 2 F, [6b] LiFePO 4 F, LiFeSO 4 F, NaMSO 4 F (M = Fe, Co, Ni, Mn, Mg, Zn, Cu), and NaMSO 4 F • 2H 2 O (M = Fe, Co, Ni, Zn) etc.…”

“…To date, a number of iron‐based electrochemically active polyanionic oxalate compounds have been reported, such as Na 2 Fe 2 (C 2 O 4 ) 3 ⋅ 2H 2 O, [4a] Li 2 Fe(C 2 O 4 ) 2 , [4b] K 2 Fe(C 2 O 4 ) 2 , [4c] KLi 3 Fe(C 2 O 4 ) 3 , [4d] Na 2 Fe(C 2 O 4 )(HPO 4 ), [4e] and Na 2 Fe(C 2 O 4 )SO 4 ⋅ H 2 O [4f] . Combining different anion sublattices in a polyanionic system in which the crystal structure was varied with different chemical composition has been found to offer tunable electrochemical activity [5] . Incorporation of fluorine is expected to increase the operating potential due to the higher ionicity of the metal‐fluoride bond, resulting in higher energy density.…”

Transition Metal Oxalate-Based Materials: An Emerging Material Family for Alkali-Ion Battery Cathodes

“…anion groups. Phosphates, − silicates, − sulfates, − pyrophosphates, − fluorides, − etc. are the typical PCs, and their electrochemical properties in different alkali-ion batteries have been deeply understood and summarized in many reviews.…”