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 Si2+/Si4+ and Fe0/Fex+ (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 cm2 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.