The research group of Dr. Rohit Ranganathan Gaddam in the Department of Chemical Engineering developed a promising new material, NaFe2-xInx(PO4)(MoO4)2 (NFIPM), poised to advance sodium-ion battery (SIB) technology. By strategically substituting iron with indium in the NASICON-type structure, the team expanded the lattice spacing, creating faster sodium-ion pathways and slashing the energy barrier for ion migration-key hurdles in SIB efficiency. First-principles calculations confirmed enhanced Na? mobility, while magnetic and electron paramagnetic resonance studies revealed a higher iron spin state, stabilizing redox activity. The optimized NFIPM10 cathode delivers a robust specific capacity of 111.85 mAh g-1 at 0.1C and exceptional longevity, retaining performance over 800 cycles at 2C, a leap in durability for SIBs. In situ X-ray diffraction demonstrated reversible single-phase reactions during charging/discharging, avoiding structural degradation common in conventional cathodes. This innovation addresses SIB challenges of slow kinetics and poor cycle life, bolstering their viability for grid-scale energy storage. While indium’s scarcity poses scalability questions, its minimal yet strategic use here balances cost and performance. The study, published in Small, underscores the potential of atomic-level doping to unlock high-performance, sustainable batteries, accelerating the shift from lithium-dependent systems to affordable, eco-friendly alternatives for a renewable energy future. More details at https://onlinelibrary.wiley.com/doi/full/10.1002/smll.202501004
