Comparison study of electrochemical and thermal stability of Na ₃ V ₂ ( PO ₄ ) ₃ in different electrolytes under room and elevated temperature

Abstract

The compatibility and reactivity between electrode materials and electrolytes is important to design safe batteries. As cathode material with guaranteed performance, the knowledge of thermal stability of the reactivity between Na 3 V 2 (PO 4 ) 3 (NVP) and carbonate-based electrolyte are still limited. Therefore, the electrochemical performance of NVP as a positive electrode material for sodium-ion batteries was tested at room temperature using coin cells with six conventional electrolytes. The results show that the charge-discharge performance of cells with different electrolytes can be ranked as cells with NaPF 6 ≈ NaTFSI > NaClO 4 based electrolytes. Moreover, the thermal reactiv-

High ionic conducting rare-earth silicate electrolytes for sodium metal batteries

“…The capacity decay can be attributed to other contributing factors, including the structural degradation of the cathode, the formation of a solid-electrolyte interphase (SEI) layer on the cathode surface, side reactions with the electrolyte, and the dissolution of active species into the electrolyte. [68][69][70][71] Additionally, the volume changes experienced by the NVP cathode during the deintercalation of Na ions can result in lattice stress, leading to cracking and detachment of the particle. This structural instability contributes to capacity decay and the occurrence of side reactions.…”

Nanoporous Cathode Material for High-Energy-Density Sodium-Ion Batteries

“…The [V 2 (PO 4 ) 3 ] 3– is a “lantern-shaped” skeleton consisting of a VO6 octahedron and a PO 4 tetrahedron co-topped along the c -axis. , In addition, Na + occupies the vacant position/channel of [V 2 (PO 4 ) 3 ] 3– , with two Na + occupying the Na(2) position (6b) along with one Na + occupying the Na(1) position (18e). When NVP is charged to voltage plateau (3.4 V), the 2 Na + in the Na(2) position are completely removed, consequently a theoretical specific capacity of 117 mAh g –1 was produced. − At that time, polyhedral channels formed by the joining of three VO 6 octahedra and three PO 4 tetrahedra have an approximate diameter equal to twice the sum of their radii of Na + and O. − The open three-dimensional framework and wide sodium-ion diffusion channels enable NVP to have excellent Na + migration ability . However, the high price and toxicity of vanadium have limited the industrialization of NVP.…”