Anode Materials for Sodium-Ion Battery

There is an urgent need to develop a highly efficient, low-cost alternative to the now-ubiquitous lithium-ion batteries (LIBs). A cheaper and less resource-critical sodium-ion battery (NIB) technology has recently gained much attention. Thus, there is also continuous research ongoing on stable, high-capacity anode materials for NIBs. Dependent on the mechanism of the electrochemical reaction, the negative electrode materials can be classified into three groups: insertion-based electrodes, alloy-based materials and conversion-type materials. Insertion compounds include soft and hard carbons as well as titanium-based oxides. The alloy-forming materials are represented by individual elements from group 14 and group 15, with Sn, Sb and P being the most prominent examples. The reaction within conversion-type materials involves the formation of new phases during sodiation that are usually structurally very different from the starting material. Transition metal oxides (Fe, Cu, and Ni) have been considered in this context due to their intrinsic stability and relative abundancy. The huge interest in the 2D materials gave rise to the layered chalcogenides, graphene, phosphorene and MX-enes as potential negative electrodes for NIBs. These classes of compounds will be described in this chapter considering their composition, structure, electrochemical performance, sustainability and cost.