The Role of Doping in Enhancing Electrochemical Performance of NASICON Na₃Zr₂Si₂PO₁₂ Electrolytes for Sodium-Ion Batteries

NASICON (sodium superionic conductor, Na3Zr2Si2PO12) is a promising electrolyte material for sodium-ion batteries due to its high ionic conductivity and excellent chemical and mechanical stability. Its inherent conductivity can be enhanced by substitutional and interstitial doping, through which foreign atoms from transition and non-transition metal groups are introduced into the crystal lattice. The superior performance of transition metal atoms can be attributed to their unique capabilities in modifying the crystal structure in ways that favor sodium-ion mobility. These dopants can alter the ion migration channels more significantly, promote efficient ion transport through the NASICON lattice, and finally result in a reduced grain resistance, giving rise to an enhancement in the overall conductivity of the solid-state electrolyte. This enhancement is crucial for optimizing the performance of sodium-ion batteries. We reviewed recent advancements in NASICON doping, with a focus on the doping strategies, the categories of dopants and the methods in relation to the synthesis. We also reviewed the impacts of doping electrolyte on the performance of sodium-ion batteries. In addition to highlighting the key achievements in NASICON doping, we else outlined the challenges in the field of NASICON solid-state electrolytes.