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• Using the character of heterointerfaces to lower voltage-hysteresis is proposed. • CuS/MnS-C heterostructure nanofibers are fabricated as binder-free LIBs electrodes. • The voltage-hysteresis values of the CuS anode are lowered to 0.30 and 0.35 V. • Capacitive capacity brought by the as-formed heterointerfaces is confirmed. Conversion-reaction anode materials always deliver high capacities when used for Li-ion batteries (LIBs). However, the large voltage-hysteresis between the discharge and charge potentials slide down the round-trip efficiency of the electrodes, which restricts their further application on commercial LIBs. Herein, an assumption that lowering the voltage-hysteresis by constructing heterostructure is proposed and further verified by CuS based electrode. As a proof of concept, CuS/MnS heterostructure nanoparticles confined by carbon layers are designed and further crosslinked into a 3D network, constructing CuS/MnS-C heterostructure nanofibers (HNFs). The as-formed heterointerfaces facilitate the charge separation and transfer, and further improve the kinetics. Meanwhile, the confinement and conductive network of the carbon nanofibers improve the structural stability and conductivity of the hybrid electrode. As a result, the voltage-hysteresis values of the CuS anode are lowered to 0.30 and 0.35 V in the well-designed CuS/MnS-C HNFs electrode, much smaller than the original values (0.82 and 0.70 V) in the CuS-C NFs electrode. Moreover, the CuS/MnS-C HNFs electrode exhibits the best excellent rate capability among their counterpart electrodes (493.5 mAh g−1 at 2.0 A g−1 with the coulombic efficiency of about 100%). This work would shed light on the development of practical conversion-reaction anode materials with low voltage-hysteresis. [ABSTRACT FROM AUTHOR]

High-capacity N, S-C/SnS 2 nanosheets KIBs anode material was prepared by an in-situ method with only one step. • N, S-C/SnS 2 nanosheets are prepared by an in-situ carbonization and sulfuration method. • N, S-doped carbon plays bi-functional role of stabilizing electrode structure and anchoring polysulfide intermediates. • The obtained N, S-C/SnS 2 nanosheet anode delivers high reversible capacity and superior cyclic stability. As indispensable components of potassium ion batteries (KIBs), anode materials are on the focus and their developments are important for boosting the application of KIBs. Tin sulfide (SnS 2) is considered as an ideal KIBs anode material owing to its high theoretical capacity (733 mAh g−1) and the unique layered structure. However, the huge volume deformation and potassium polysulfide intermediates dissolution hinder the enhancement of the electrochemical performance of SnS 2 anode. Herein, SnS 2 nanosheets supported by N, S-doped carbon (N, S-C/SnS 2 nanosheets) were synthesized by an in-situ carbonization and sulfuration method with one step. In the formed architecture, the N, S-doped carbon not only works as matrix to stabilize the microstructure of the hybrid material, but also serves as the reservoir to trap polysulfides for alleviating the loss of sulfur element in SnS 2. Thanks to these merits, a high reversible capacity (614.8 mAh g−1 at 0.1 A g−1), as well as good rate capability (104.5 mAh g−1 at 2.0 A g−1) are achieved by the N, S-C/SnS 2 nanosheets electrode. This work offers a concise method to construct SnS 2 hybrid material, and demonstrates that K+ ion storage property of conversion-alloy reaction mechanism sulfide anodes can be remarkably enhanced by elegant structure design. [ABSTRACT FROM AUTHOR]