Interlayer gap widened α-phase molybdenum trioxide as high-rate anodes for dual-ion-intercalation energy storage devices

Employing high-rate ion-intercalation electrodes represents a feasible way to mitigate the inherent trade-off between energy density and power density for electrochemical energy storage devices, but efficient approaches to boost the charge-storage kinetics of electrodes are still needed. Here, we demonstrate a water-incorporation strategy to expand the interlayer gap of alpha-MoO3, in which water molecules take the place of lattice oxygen of alpha-MoO3. Accordingly, the modified alpha-MoO3 electrode exhibits theoretical-value-close specific capacity (963 C g(-1) at 0.1mV s(-1)), greatly improved rate capability (from 4.4% to 40.2% at 100 mVs(-1)) and boosted cycling stability (from 21 to 71% over 600 cycles). A fast-kinetics dual-ion-intercalation energy storage device is further assembled by combining the modified alpha-MoO3 anode with an anion-intercalation graphite cathode, operating well over a wide discharge rate range. Our study sheds light on a promising design strategy of layered materials for high-kinetics charge storage.