A bismuth oxide electrode, delivering high capacity, as an anode material for sodium-ion batteries was simply prepared. The electrochemical properties of bismuth oxide were studied by operando X-ray absorption near edge structure spectroscopy and ex situ X-ray diffraction methods. A bismuth oxide/carbon composite showed enhanced cycle stability at high current densities.

Intercalation‐based cathodes typically rely on the cationic redox activity of transition metals to deliver capacity, but, recently, anionic redox chemistry has emerged as a way to increase the energy density of rechargeable batteries. However, the irreversible structural disorder and voltage fading accompanying oxygen release are major problems preventing commercial use. To overcome these limitations, the connection between structural stability and anionic redox activity must be understood. Here, we present a review of theoretical and experimental progress in anionic redox in sodium intercalation cathodes. First, the effects of structural factors including stacking sequences and cationic vacancies on the reversible capacity originating from anionic redox are discussed. Second, the effects on anionic redox activity of cationic substitution with alkaline earth metals (Li or Na) and the coordination environment are highlighted. Third, the progress and challenges facing materials based on 3d/4d/5d metals are reviewed. Finally, research directions for the development of anionic redox active materials are outlined.

SnS nanoparticles embedded in N-doped carbon are prepared by using Sn(salen) and exhibited outstanding electrochemical performance for lithium-ion batteries.