Dec 3, 2024
4:15pm - 4:30pm
Hynes, Level 3, Ballroom C
Hugh Smith1,Gihyeok Lee2,Sravan Kumar Bachu1,Aubrey Penn1,Victor Venturi1,Yifan Gao1,Ryan Davis3,Kevin Stone3,Adrian Hunt4,Iradwikanari Waluyo4,Eli Stavitski4,Wanli Yang2,Iwnetim Abate1
Massachusetts Institute of Technology1,Lawrence Berkeley National Laboratory2,SLAC National Accelerator Laboratory3,Brookhaven National Laboratory4
Hugh Smith1,Gihyeok Lee2,Sravan Kumar Bachu1,Aubrey Penn1,Victor Venturi1,Yifan Gao1,Ryan Davis3,Kevin Stone3,Adrian Hunt4,Iradwikanari Waluyo4,Eli Stavitski4,Wanli Yang2,Iwnetim Abate1
Massachusetts Institute of Technology1,Lawrence Berkeley National Laboratory2,SLAC National Accelerator Laboratory3,Brookhaven National Laboratory4
Sodium-ion batteries have the potential to meet growing demand for energy storage due to their low costs stemming from natural resource abundances, but their cathode energy densities must be improved to be comparable to those of lithium-ion batteries. One strategy is accessing high voltage capacity through high-valent redox reactions. Such reactions usually cause instability in cathode materials, but Na<sub>2</sub>Mn<sub>3</sub>O<sub>7</sub> has demonstrated excellent performance and reversibility in the high-valent regime due to its unique lattice structure with ordered Mn vacancies. This work expands the universality of the ordered vacancy as a design principle and increases the material candidates with such exceptional electrochemical behavior. Our approach involves synergizing cationic ordered vacancies with tunable metal-ligand hybridization through partial metal substitution. The impact of substitution in the low- and high-valent regimes is investigated through advanced microscopy and in-situ synchrotron X-ray characterization techniques. Substitution leads to larger specific capacities, enhanced cycle stability, and superior rate performance. This study lays the foundation for developing new cathode materials with stable high-valent redox through substitution of redox-active transition metals by employing cationic ordered vacancies and partial transition metal substitution as design principles in tandem.