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Abstract:Interface engineering strategy shows great promise in promoting the reaction kinetic and cycling performance in the field of electrochemical energy storage application. In this work, an in-situ interface growth strategy is proposed to introduce a robust and conducting MoGe2 alloy interphase between the electrochemical active Ge nanoparticle and flexible MoS2 nanosheets to modulate their Li-ion storage kinetics.The structural evolution processes of the Ge@MoGe2@MoS2 composite are unraveled, during which the initially-generated Ge metals serve as a crucial reduction mediator in the formation of MoGe2 species bridging the Ge and MoS2. The as-generated MoGe2 interface, chemically bonding with both Ge and MoS2, possesses multi-fold merits, including the maintaining stable framework of electrochemically inactive Mo matrix to buffer the strain-stress effect and the ‘‘welding spot" effects to facilitate the efficient Li+/eàconduction. As well, the introduction of MoGe2 interface leads to a unique sequential lithiation/de-lithiation process, namely in the order of the electrochemically active MoS2-MoGe2-Ge during lithiation and vice versa, during which the electrode strain could be more effectively released. Benefited from the robust and rigid MoGe2 interface, the delicately designed Ge@MoGe2@MoS2 composite exhibits an improved charge/discharge performances(866.7 mAh gà1 at 5.0 A gà1 and 838.5 mAh gà1 after 400 cycles) while showing a high tap density of 1.23 g cmà3. The as-proposed in-situ interface growth strategy paves a new avenue for designing novel high-performance electrochemical energy storage materials.
Volume:v.56
Issue:05
Translation or Not:no