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Conducting and Lithiophilic MXene/Graphene Framework for High-Capacity, Dendrite-Free Lithium–Metal Anodes

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posted on 03.12.2019, 20:13 by Haodong Shi, Chuanfang John Zhang, Pengfei Lu, Yanfeng Dong, Pengchao Wen, Zhong-Shuai Wu
Li-metal anode is widely acknowledged as the ideal anode for high-energy-density batteries, but seriously hindered by the uncontrollable dendrite growth and infinite volume change. Toward this goal, suitable stable scaffolds for dendrite-free Li anodes with large current density (>5 mA cm–2) and high Li loading (>90%) are highly in demand. Herein, a conductive and lithiophilic three-dimensional (3D) MXene/graphene (MG) framework is demonstrated for a dendrite-free Li-metal anode. Benefiting from its high surface area (259 m2 g–1) and lightweight nature with uniformly dispersed lithiophilic MXene nanosheets as Li nucleation sites, the as-formed 3D MG scaffold showcases an ultrahigh Li content (∼92% of the theoretical capacity), as well as strong capabilities in suppressing the Li-dendrite formation and accommodating the volume changes. Consequently, the MG-based electrode exhibits high Coulombic efficiencies (∼99%) with a record lifespan up to 2700 h and is stable for 230 cycles at an ultrahigh current density of 20 mA cm–2. When coupled with Li4Ti5O12 or sulfur, the MG-Li/Li4Ti5O12 full-cell offers an enhanced capacity of 142 mAh g–1 after 450 cycles, while the MG-Li/sulfur cell delivers an improved rate performance, implying the great potential of this 3D MG framework for building long-lifetime, high-energy-density batteries.

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