Highly-cyclable Na-ion battery exploiting a nanostructured tin-carbon anode, layered-oxide P3/P2 cathode and a glyme-based electrolyte

Alternative materials to (purely) carbon-based anodes could enhance the energy density of sodium-ion batteries, and thus favor their complementarity to lithium-ion batteries. This work provides a viable setup of Na-ion cells
combining a P3/P2 sodium-deficient layered cathode and a tin-carbon Na-alloying anode with a glyme-based electrolyte. Galvanostatic cycling in sodium half-cells of the water-processed alloying anode with sodium car-boxymethyl cellulose (CMC) binder shows a maximum capacity of ~260 mAh g$^{-1}$, a capacity retention exceeding 70 % after 150 cycles, and an average Coulombic efficiency over 99 %. The multi-metal cathode evidences a great cycling stability over 100 cycles, with average Coulombic efficiency between 99.5 and 99.6 % as favored by the presence of Al$^{3+}$ ions in its structure. Full Na-ion batteries exploiting ad hoc chemically-sodiated tin-based anode and sodium-deficient layered cathode operate with average working voltage of 3 V, and maximum capacity of 120 mAh g$^{-1}$ retained for 95 % over 100 cycles in the best experimental setup. The rationally designed full-cell reaches theoretical energy density between 310 and 250 Wh kg$^{-1}$ as referred to the cathode weight.