摘要：SummaryConfining the particle-electrolyte interactions to the particle surface in electrode materials is vital to develop sustainable and safe batteries. Micron-sized single-crystal particles offer such opportunities. Owing to the reduced surface area and grain boundary-free core, particle-electrolyte interactions in micron-sized single-crystal particles will be confined to the particle surface. Here, we reveal the potential of such materials in sodium-ion batteries. We synthesized and investigated the chemical, electrochemical, and thermal properties of single-crystalline P2-type Na0.7Mn0.9Mg0.1O2as a cathode material for sodium-ion batteries. Single-crystalline Na0.7Mn0.9Mg0.1O2with a mean particle size of 8.1 μm exhibited high cycling and voltage stability. In addition, the exothermic heat released by the charged single-crystal Na0.7Mn0.9Mg0.1O2cathodes was four times lower than that of the corresponding polycrystalline Na0.7Mn0.9Mg0.1O2. This significantly enhances the thermal stability of electrode materials and possibly mitigates thermal runaways in batteries. Surprisingly, single crystals of Na0.7Mn0.9Mg0.1O2were relatively stable in water and ambient atmosphere.Graphical abstractDisplay OmittedHighlights•Micron-sized single crystals (MSSC) of P2-Na0.7Mn0.9Mg0.1O2were investigated for SIBs•They showed high cycling and voltage stability compared to the polycrystalline sample•Exhibited four times lower exothermic heat evolution than the polycrystalline sample•MSSC cathode showed higher stability in air and waterElectrochemistry; Energy systems; Materials science
