Freestanding flexible Si nanoparticles-multiwalled carbon nanotubes composite anodes for Li-ion batteries and their prelithiation by stabilized Li metal powder

Freestanding flexible Si nanoparticles-multiwalled carbon nanotubes (SiNPs-MWNTs) composite paper anodes for Li-ion batteries (LIBs) have been prepared using a combination of ultrasonication and pressure filtration. No conductive additive, binder, or metal current collector is used. The SiNPs-MWNTs composite electrode material achieves first cycle specific discharge and charge capacities of 2298 and 1492 mAh/g, respectively. To address the first cycle irreversibility, stabilized Li metal powder (SLMP) has been utilized to prelithiate the composite anodes. As a result, the first cycle irreversible capacity loss is reduced from 806 to 28 mAh/g and the first cycle coulombic efficiency is increased from 65% to 98%. The relationship between different SLMP loadings and cell performance has been established to understand the prelithiation process of SLMP and to optimize the construction of Si-based cells. A cell containing the prelithiated anode is able to deliver charge capacity over 800 mAh/g without undergoing the initial discharge process, which enables the exploration of novel cathode materials.