Synthesis and Electrochemical Characterization of Lithium Carboxylate 2D Compounds as High-Performance Anodes for Li−Ion Batteries

The large-scale utilization of Li-ion batteries in electric vehicles requires urgent development of cost-effective and high-performance electrode materials. Herein, we report the synthesis of conjugated carboxylate (Li₄C₈H₂O₆) and non-conjugated carboxylate (Li₄C₄H₂O₆) by using a simple solvothermal method and its utilization as anode materials in Li-ion batteries. Atomic force microscopy reveals that as-prepared Li₄C₈H₂O₆ and Li₄C₄H₂O₆ possess a sheet-like morphology with a thickness of 3–5 nm. An initial discharge capacities of 251.7 mAh/g and 251.6 mAh/g at a current density of 50 mA/g can be obtained for Li₄C₈H₂O₆ and Li₄C₄H₂O_6, respectively. In addition, Li₄C₈H₂O₆ is combined with a small amount (5 wt. %) of graphene and nano-Si to enhance the cyclic performance and specific capacity. Consequently, Li₄C₈H₂O₆/graphene and Li₄C₈H₂O₆/nano-Si composites rendered a high discharge capacity of 350 mAh/g and 240 mAh/g, respectively, at a relatively higher current density of 100 mA/g. These results demonstrate that lithium carboxylates are promising anode materials for Li-ion batteries.