Sodium-Ion Batteries

2Design Principles for Sodium‐Ion Batteries

2.1 Introduction

The working principles of sodium‐ion batteries (SIBs) are similar to lithium‐ion batteries (LIBs) (Figure 2.1) [1]. For the sodium‐containing cathode materials, various materials have been reported including polyanionic compounds, transition metal oxides with tunnel or layered structures, organic cathodes, and Prussian blue analogs. Among them, transition metal oxides (Na_0.44MnO₂, Na₄Mn₉O₁₈, Na_1−xNi_0.5Mn_0.5O₂, NaNi_1/3Mn_1/3Co_1/3O₂, Na_xCoO₂, Na_0.6Fe_0.5Mn_0.5O₂, etc.) and polyanionic phosphates (Na₃V₂(PO₄)₃, NaFePO₄, Na₂FePO₄F, Na₃V₂(PO₄)₂F₃, etc.) have been extensively investigated [2]. SIB anodes include the following categories: (i) intercalation anodes, such as (Na superionic ion ...