Cooperative Conformational Change of a Single Organic Molecule for Ultrafast Rechargeable Batteries

We unveil that the conformational change of a single organic molecule during the redox reaction leads to impressive battery performance for the first time. We propose the model material, a phenoxazin-3-one derivative, as a new redox-active bioinspired single molecule for the Li-ion rechargeable battery. The phenoxazin-3-one cathode delivered a high discharge capacity (298 mAh g–1) and fast rate capability (65% capacity retention at 10 C). We elaborate the redox mechanism and reaction pathway of phenoxazin-3-one during Li+-coupled redox reaction. The molecular structure alteration of phenoxazin-3-one during the lithium-coupled electron transfer reaction enables strong π–π interaction between 2Li-phenoxazin-3-one and carbon, which was evidenced by operando Raman spectroscopy and density functional theory calculation. Our work provides in-depth understanding about the conformational molecular switch of the single molecule during Li+-coupled redox reaction and insight into the design of a new class of organic electrode materials.