Niobium/tantalum-based materials: Synthesis and applications in electrochemical energy storage

Abstract

As transition metals, Nb and Ta share similar physical and chemical properties, exhibiting high melting and boiling points. Materials coexisting with Nb and Ta have attracted much attention in electrochemical energy storage, which are attributed to their unique crystal structures. However, Nb2O5 has the drawback of having a low electronic conductivity, which results in poor rate capability. Thus, Nb-based materials, including Nb-based oxides, Nb-based oxides/carbon and Nb-based carbides/nitrides, have been explored. This review discusses the use of Nb/Ta-based materials in electrochemical energy storage applications, including rechargeable batteries (e.g., lithium-ion batteries and sodium-ion batteries), supercapacitors and hybrid supercapacitors. In addition, the bottlenecks and challenges of using these materials are briefly discussed.