Research

Revealing the interfacial kinetic mechanisms in high-entropy doped Na3V2(PO4)3 through electrochemical investigation and distribution of relaxation times- By Prof. R. S. Dhaka

We design a high-entropy doped NASICON cathode, Na3V1.9(CrMoAlZrNi)0.1(PO4)3 and investigate its electrochemical performance for sodium storage to understand the diffusion mechanism including distribution of relaxation times analysis of interfacial kinetics. This trace doping induces high-entropy mixing at the vanadium site, tuning the lattice and enhancing specific capacity, activating V4+/V5+ redox couple 3.95 V. Interestingly, it exhibits a reversible capacity of 119 mAh g−1 at 0.1 C, and demonstrate remarkable stability of 68% over 1000 cycles at 10 C. The calculated diffusion coefficient using different electrochemical protocols is found in the range of 10−11–10−13cm2s−1. The systematic investigation of temperature and voltage-dependent impedance data using the distribution of relaxation times provides deeper insights into the underlying charge-transfer and transport processes. The full cells with hard carbon deliver 326 Wh kg−1 (w. r. t. cathode mass) at ≈3.2 V and retained ∼79% capacity over 100 cycles at 2 C. Our study opens new avenues for developing high-entropy doped cathodes for enhanced structural stability, extended redox activity, and optimized electrochemical kinetics for practical implementation of sodium-ion batteries.

Link : https://doi.org/10.1016/j.jpowsour.2026.241212 , 25 August 2026

Contact Details

R. S. Dhaka
Department of Physics,
rsdhaka@physics.iitd.ac.in