Tin Anode for High-Energy-Density Na-Ion Batteries

Tin (Sn) is a promising anode material for sodium-ion batteries (SIBs) due to its high theoretical specific capacity (847 mAh g −1 ) and volumetric capacity (6238 mAh cm −3 ). In addition, Sn is a commodity and can be readily sourced. However, alloy anodes tend to suffer from a low initial Coulombic efficiency (ICE) and severe capacity loss due to extensive volume expansion (∼420% for Sn) during electrochemical cycling. In this work, commodity-sourced Sn is used (with an electrode active material composition of >99% Sn) to demonstrate how these traditional challenges can be overcome without major modifications. When paired with a NaCrO 2 (NCrO) cathode in a full cell, a high specific energy of 178 Wh kg −1 and volumetric energy density of 417 Wh L −1 can be achieved. This work highlights the opportunities for alloy materials such as Sn to enable high energy density SIBs.