The advent of manganese-substituted sodium vanadium phosphate-based cathodes for sodium-ion batteries and their current progress: a focused review

Na₃V₂(PO₄)₃ (NVP) is a member of the sodium superionic conductor (NASICON) family and has been extensively studied as a cathode material for sodium-ion batteries (SIBs) for more than three decades due to its stable voltage platform, high capacity, and stable cycle life. However, the presence of toxic and expensive V elements restricts the utilization of NVP-based SIBs. To overcome this, energy researchers have employed a cation swapping approach, which resulted in new NASICON-type manganese-substituted sodium vanadium phosphate (MSVP) cathodes for SIBs. Na₄MnV(PO₄)₃ (NMVP) is among the new generation of high-energy, risk-free NASICON-type MSVP cathodes, and its use for SIBs was documented in 2016. There has been strong acceptance of MSVP-based cathodes among materials researchers due to their cost and economic advantages. In a short period, considerable work has been done to increase the commercial potential of MSVP-based cathodes for SIBs. This review summarizes the pioneering developments made with MSVP-based cathodes, with a special focus on their structural and electrochemical evolution. This review can serve as a reference for future energy researchers fabricating highly efficient and safer NASICON cathodes not only for SIBs but also for other energy storage applications.