Distorted Iron Oxide Quantum Dots with Unprecedented Fast‐Charging Capability for High‐Energy and High‐Power Lithium Storage

Abstract

AbstractHigh‐energy lithium‐ion storage devices that can be used at high rates are the eternal pursuit in electrical vehicles and various other applications. However, existing anode materials are difficult to achieve the desired fast‐charging reaction. Here, a new type of distorted iron oxide quantum dots is reported containing abundant crystallographic defects and edge dislocations encapsulated in carbon (d‐Fe2O3 QDs@C). When used as the anode, it achieves nearly complete six‐electron reaction close to the theoretical capacity. More importantly, it harvests exceptional fast‐charging capability, delivering over half of the capacity (475 mAh g−1) in <1 min. Even at its fastest, the distorted structure can still harvest 182 mAh g−1 within just 7 s, far outperforming all existing Fe‐based anodes and is unprecedented. Theoretical calculations reveal that the exceptional fast‐charging characteristic originates from the optimized ion adsorption and significantly reduced ion migration energy barrier, thus ensuring that the electrode can still effectively operate at ultra‐large currents. This promotional effect is further verified by ex situ characterization. Besides, the constructed lithium‐ion capacitor also exhibits prominent energy/power output with excellent stability. These findings emphasize the superiority of distorted structure in fast‐charging capability and afford novel insights into the development of next‐generation high performance electrodes.