In-situ construction of conducting alloy interphase towards modulating Li-ion storage kinetics

• 作者: Lingjie Li Dandan Wang Xiaoxia Xu Xiaosong Guo Jing Liu Changming Mao Zhonghua Zhang Guicun Li
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（5）
• 页码范围: 395-403
• 页数: 9页
• 语种: 英文

摘要

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+/e-conduction.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 g-1 at 5.0 A g-1 and 838.5 mAh g-1 after 400 cycles) while showing a high tap density of 1.23 g cm-3.The as-proposed in-situ interface growth strategy paves a new avenue for designing novel high-performance electrochemical energy storage materials.