Silicon nanofilms as anode materials for flexible lithium ion batteries

摘要

Silicon (Si)-based anodes demonstrate great potential for the revolutionary enhancement in the energy storage of Li-ion cells. Unfortunately, these materials suffer from several shortcomings, such as high electrical resistivity, low Li diffusivity and significant volume change during operation, which limit their stability and power characteristics. To overcome these limitations, we fabricate Si-based anodes by deposition of Si thin film on multiwalled carbon nanotube (MWCNT) sheet using RF magnetron sputtering. The characterization of MWCNT-Si composites by spectroscopy techniques confirmed the deposition of amorphous Si nanofilms. The as-prepared MWCNT-Si nanocomposites were tested as anode material in half-cell using Li metal as counter and reference electrodes, and in full cell using LiFePO4 as cathode. MWCNT-Si composites exhibited stable electrochemical performance during 50 cycles with specific reversible capacity greater than 2000 mAh/g for 130-nm Si film. MWCNT-Si//LiFePO4 full cell delivered a voltage of 2.9 V and displayed satisfactory cycling performance during 50 cycles.