Polyanionic material, specifically the NASICON‐type material, is considered a promising cathode material for Na‐ion batteries (SIBs) because of its stable structure and high operating voltage. Further, it improves the energy density correlated with the well utilization of all Na in the compound. For Na3V2(PO4)2F3 (NVPF), the extraction of the third Na, reported as the electrochemical inactivated, can be realized at a high voltage region while forming an irreversible tetragonal phase. In this study, we introduce Ti doping to the Na2VTi(PO4)2F3 (NVTPF) material; we reveal that the Ti‐doped NVTPF could effectively suppress the irreversible phase transformation, thus successfully harnessing Na in a wide voltage range. Experimental study discloses that the Ti‐substituted Na2VTi(PO4)2F3 could take up the Na+ from Amam phase to Cmc21 phase between 1.0 V and 4.8 V reversibly accounting for the 2 Na+ transportation that shows favorable Na+ kinetics and structural stability. Our research provides the strategy to stabilize the polyanion structure upon charging at a high voltage range and inspires the utilization of full sodium in the polyanionic materials, which could be considered as a material design for future conventional applications.

Sodium-ion batteries, which are viewed as the alternative candidate for lithium-ion batteries, are now receiving extensive attention in recent years. This is because of the earth's abundance, the widespread sodium resource, and the low cost of battery production. Despite tremendous effort has been made to improve the battery performance of sodium-ion batteries, several serious problems hinder the large-scale practical applications. These problems such as low energy density and efficiency, poor cycle life, and low charge/discharge rate are largely determined by fundamental mechanism issues of electrode materials that are not sufficiently understood yet. Therefore multiple techniques should be used to get an in-depth understanding of material properties.In this review, a comprehensive overview of the material characterization technique is provided and hope it could improve the battery research for all the scientific researchers.