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The relatively low operating voltage window is the main factor limiting the energy density of aqueous energy storage devices. The delicate design of heterostructured electrode materials can efficiently increase the intrinsic electrochemical performance through synergistic effects. For the first time, to broaden the voltage window of aqueous supercapacitors the synergistic effect between boroncarbonitrides (BCN) and built‐in electric field existing in heterostructures is designed to utilize. Based on this design concept, MnO/MnS@BCN electrode materials are synthesized, in which the synergistic effect can effectively strengthen the storage of electrolyte ions on the electrode surface, thus inhibiting the electrolysis of H2O and eventually broadening the voltage window of aqueous supercapacitor. In MnO/MnS@BCN‐based symmetrical supercapacitors, the voltage window of the device is extended from 1.2 V (single‐component) to 2 V, with the energy density enhanced to 75.0 W h kg−1. The strategy blazes an efficient and convenient path to broaden the intrinsic voltage window of transition metal oxide supercapacitors. [ABSTRACT FROM AUTHOR]

Combining 2D MoS2 with other transition metal sulfide is a promising strategy to elevate its electrochemical performances. Herein, heterostructures constructed using MnS nanoparticles embedded in MoS2 nanosheets (denoted as MnS‐MoS2) are designed and synthesized as anode materials for lithium/sodium‐ion batteries via a facile one‐step hydrothermal method. Phase transition and built‐in electric field brought by the heterostructure enhance the Li/Na ion intercalation kinetics, elevate the charge transport, and accommodate the volume expansion. The sequential phase transitions from 2H to 3R of MoS2 and α to γ of MnS are revealed for the first time. As a result, the MnS‐MoS2 electrode delivers outstanding specific capacity (1246.2 mAh g−1 at 1 A g−1), excellent rate, and stable long‐term cycling stability (397.2 mAh g−1 maintained after 3000 cycles at 20 A g−1) in Li‐ion half‐cells. Superior cycling and rate performance are also presented in sodium half‐cells and Li/Na full cells, demonstrating a promising practical application of the MnS‐MoS2 electrode. This work is anticipated to afford an in‐depth comprehension of the heterostructure contribution in energy storage and illuminate a new perspective to construct binary transition metal sulfide anodes. [ABSTRACT FROM AUTHOR]