A review of niobium oxides based nanocomposites for lithium-ion batteries, sodium-ion batteries and supercapacitors

Batteries and hybrid supercapacitors (SCs) are now playing a pivotal role in the development of electric vehicles, consumer electronics and large-scale power stations. Niobium-oxides-based materials and their composites have recently received a great attention for their applications in lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and pseudocapacitors because of their advantages, such as quasi-2D networks for fast ion insertion/extraction, rich redox chemistry, and high chemical stability. However, several challenges, including poor inherent conductivities and limited/superficial electrochemical active sites, should be overcome before practical applications. In this paper, the recent advancement of the materials preparation, synthesis, characterization, and performance validation as well as fundamental understanding of the functional mechanisms are comprehensively reviewed. Several technical challenges and strategies are respectively analyzed and utilized to improve the materials’ electrochemical performances, including morphology control, surface engineering, doping and construction of composite electrodes. Indeed, the charge storage mechanisms of the materials with different crystal structures are summarized and discussed. Several research directions toward the development, practical applications and commercialization of the related electrochemical energy devices are also proposed for enhancing the performance of niobium oxides and their composites. • Key strategy for improving electrochemical performance of Nb 2 O 5 -based materials is proposed. • Strategy developing Nb 2 O 5 -based materials with high performance is proposed. • An insight into the future research direction of Nb 2 O 5 -based materials is highlighted.