Alluaudite Battery Cathodes

Abstract

Rechargeable batteries have emerged as ubiquitous and indispensable technologies of the 21st century, propelling myriads of consumer electronics and ushering a new era of electric vehicles and stationary grid storage. Since the commercialization of Li‐ion batteries by SONY (approximately in the year 1991), the secondary battery sector has seen unprecedented growth with diverse applications touching global populations across socioeconomic strata. There is a steady quest to develop a wide range of batteries to cater diverse global demands from milliwatt‐scale electronics to megawatt‐scale grid‐storage applications. In this journey, Li‐ion batteries are complemented by various post‐Li‐ion chemistry (e.g., Na+, K+, Mg2+, Ca2+, and Al3+‐ion batteries), conversion mechanism‐based systems (e.g., Li–S, Na–S, and Li–O2) as well as renewed development of pre‐Li‐ion era technologies like aqueous batteries. Cathodes sit at the core with command over the net cost and performance of batteries. Various polyanionic cathodes have been developed to date, often guided by structure of naturally occurring minerals. One such mineral system is alluaudite, named after French geologist François Alluaud. The current article portrays the discovery and development of the alluaudite class of polyanionic cathode materials for rechargeable batteries. The structure and electrochemical properties of various alluaudite insertion materials are gauged along with possible future perspectives.

Aqueous spray-drying synthesis of alluaudite Na2+2xFe2−x(SO4)3 sodium insertion material: studies of electrochemical activity, thermodynamic stability, and humidity-induced phase transition

“…Alluaudites, named after its discoverer Franҫois Alluaud II, are a group of alkali metal phosphate-based naturally occurring minerals having open frameworks as well as broad tunnels for easy alkali ion passage [7]. The general formula of alluaudite-based materials can be written as A (1)A( 2)M(1)M(2) 2 (XO 4 ) 3 , where A denotes the alkali ions, M denotes the transition metal ions, and X could be S, P, As, V, Mo, or W [8]. A and M (1) sites are occupied by monovalent (Na + , Li + ) or divalent cations (Ca 2+ , Mg 2+ ) while the M(2) site can be filled with divalent (Mn 2+ , Fe 2+ ) or trivalent cations (Mn 3+ , Fe 3+ , In 3+ ).…”

Unlocking New Redox Activity in Alluaudite Cathodes through Compositional Design

“…[35][36][37][38][39] Their general formula is A2M(1)2M(2)(XO4)3 for X = P, V, and A2M(1)M(2)(XO4)3 for X = S, with A = Li, Na. The A2M(1)2M(2)(XO4)3 structure (monoclinic C2/c space group 40 ) is shown in Figure 1a. Alluaudites exhibit edgesharing MO6 octahedra that form kinked one-dimensional (1D) chains of M(2) octahedral pairs alternating with an M(1) octahedron (Figure 1b).…”

Towards the High Phase Purity of Nanostructured Alluaudite-Type Glass-Ceramics Cathode Materials for Sodium Ion Batteries

“…The values varied from 50 to 140 mAh/g, while most of the papers reported values about 100 mAh/g. A review of such parameters can be found, e.g., in [ 7 ]. Among the compositions containing iron, vanadium, and manganese, e.g., Na Fe V(PO ) [ 8 ] and Na Mn V(PO ) [ 9 ] have been synthesized and studied.…”