Two-Dimensional Beidellite/Carbon Superlattice for Boosting Lithium-Ion Storage Performance.

Two-dimensional Fe-beidellite/carbon (Fe-BEI@C) superlattice-like heterostructure was prepared by intercalation of glucose in the gallery of layered Fe-BEI followed by calcination. The interlaminar and superficial carbon coating enables Fe-BEI to have good rate performance, fast lithium-ion diffusion, and high pseudocapacitance contribution, leading to excellent lithium storage performance as anode material for lithium-ion batteries (LIBs). The Fe-BEI@C/Li half cell delivers a maximum specific capacity of 850 mAh·g -1 at 0.5 A·g -1 and has a 92.3% retention rate after 100 cycles along with a high-rate performance of 403 mAh·g -1 at 5 A·g -1 . The reversible valence state change of Si 2+ /Si 4+ and Fe 0 /Fe x + (0 < x < 3) in electrochemical cycles are realized without collapse of layered structure. Additionally, the Fe-BEI@C heterostructure displays a high Li + diffusion coefficient of 10 -13 ∼10 -10 cm 2 s -1 , illustrating fast Li + transfer in the interlayer of Fe-BEI@C heterostructure. Dynamic analysis reveals that the Si redox reaction is almost dominated by surface control and that of Fe is mainly diffusion-controlled. This work has exploited a novel layered silicate as anode material for LIBs and developed a molecular-level carbon hybridization method to improve their electrochemical performance, which is meaningful for the application of layered silicate in the energy-storage field.