| Summary: | Sodium-ion batteries (SIBs) have demonstrated noticeable development since the 2010s, being complementary to the lithium-ion technology in predominantly large-scale application niches. The projected SIB market growth will inevitably lead to the generation of tons of spent cells, posing a notorious issue for proper battery lifecycle management, which requires both the establishment of a regulatory framework and development of technologies for recovery of valuable elements from battery waste. While lithium-ion batteries are mainly based on layered oxides and lithium iron phosphate chemistries, the variety of sodium-ion batteries is much more diverse, extended by a number of other polyanionic families (crystal types), such as NASICON (Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>), Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3<i>−y</i></sub>O<i><sub>y</sub></i>, (0 ≤ <i>y</i> ≤ 2)<i>,</i> KTiOPO<sub>4</sub>-type AVPO<sub>4</sub>X (A—alkali metal cation, X = O, F) and β-NaVP<sub>2</sub>O<sub>7</sub>, with all of them relying on vanadium and phosphorous—critical elements in a myriad of industrial processes and technologies. Overall, the greater chemical complexity of these vanadium-containing phosphate materials highlights the need for designing specific recycling approaches based on distinctive features of vanadium and phosphorus solution chemistry, fine-tuned for the particular electrodes used. In this paper, an overview of recycling methods is presented with a focus on emerging chemistries for SIBs.
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