Authors: Hayong Song, KwangSup Eom
Published: 2020-06-10
Source: Full article
AbstractIn this work, a full‐cell sodium‐ion battery (SIB) with a high specific energy approaching 300 Wh kg−1 is realized using a sodium vanadium fluorophosphate (Na3V2(PO4)2F3, NVPF) cathode and a tin phosphide (SnPx) anode, despite both electrode materials having greatly unbalanced specific capacities. The use of a cathode employing an areal loading more than eight times larger than that of the anode can be achieved by designing a nanostructured nanosized NVPF (n‐NVPF) cathode with well‐defined particle size, porosity, and conductivity. Furthermore, the high rate capability and high potential window of the full‐cell can be obtained by tuning the Sn/P ratio (4/3, 1/1, and 1/2) and the nanostructure of an SnPx/carbon composite anode. As a result, the full‐cell SIBs employing the nanostructured n‐NVPF cathode and the SnPx/carbon composite anode (Sn/P = 1/1) exhibit outstanding specific energy (≈280 Wh kg−1(cathode+anode)) and energy efficiency (≈78%); furthermore, the results are comparable to those of state‐of‐the‐art lithium‐ion batteries.