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

Yu, Minghao; Shao, Hui; Wang, Gang; Yang, Fan; Liang, Chaolun; Rozier, Patrick; Wang, Cai-Zhuang; Lu, Xihong et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

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 α-MoO<sub>3</sub>, in which water molecules take the place of lattice oxygen of α-MoO<sub>3</sub>. Accordingly, the modified α-MoO<sub>3</sub> electrode exhibits theoretical-value-close specific capacity (963 C g<sup>-1</sup> at 0.1 mV s<sup>-1</sup>), greatly improved rate capability (from 4.4% to 40.2% at 100 mV s<sup>-1</sup>) 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 α-MoO<sub>3</sub> 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.