Controllable growth of carbon nanosheets in the montmorillonite interlayers for high-rate and stable anode in lithium ion battery

Abstract

A novel insertable and pseudocapacitive Li⁺ ion material for highly ordered layered montmorillonite/carbon is explored in the present study. The commercially available protonated montmorillonite and 3,3'-diaminobenzidine act as starting materials to synthesize the layered material via hydrothermal intercalation, oxidative polymerization and carbonization. This method of preparing montmorillonite/carbon nanocomposite exhibits several advantages. To be specific, raw materials are low cost and naturally abundant; the montmorillonite can undergo proton exchange easily to form a permutable proton-type material, and the protons in the layered nanocomposite can be directly substituted by the polymerizable molecules (e.g., 3,3'-diaminobenzidine). Accordingly, a sheet-like montmorillonite/carbon layered nanocomposite is achieved with the carbon stacking on the montmorillonite substrate for the intercalation behavior. As revealed from the electrochemical results, montmorillonite/carbon nanocomposite can deliver a high reversible capacity of 1432 mA h g^-1 at 50 mA g^-1 and superior rate capacity of 920 mA h g^-1 at 10 000 mA g^-1 for the lithium ion battery. Furthermore, the full cell with LiFePO₄ as cathode and montmorillonite/carbon as anode maintains 94% capacity retention over 50 cycles as well as high coulombic efficiency.