Flexible aramid current collector loaded with D-CNTs@SiO2 @N-doped carbon composite for enhanced electrochemical performance

Abstract

SiO2 exhibits impressive theoretical specific capacity (1965 mAh g−1) as the anode of lithium-ion batteries. However, its commercial development is seriously hindered by security risks due to capacity fading and sharp fluctuations. Herein, we apply defect engineering to SiO2/C composites and report a stable preparation method of D‐CNTs@SiO-CNTs@SiO2 @N-C sandwich nanorods. The sandwich structure effectively alleviates the severe mechanical stress caused by volume expansion. The carbon materials with the structural defects provides abundant lithium storage sites for the electrode. It alleviates the influence of the low capacitance of C in the SiO2/C composite on the overall capacity. Furthermore, the flexibility and sulfur carrying capacity of copper foil are not outstanding, which limits the rate capacity of the battery. Therefore, aramid conductive fibers(AF) with excellent electrical conductivity were prepared to load D-CNTs@SiO2 @N-C (D-AF) in this work. The unique flexible skeleton in D-AF could realize the internal encapsulation of the active substances and adapt to the deformation of the electrode sheet under stress. Moreover, the dense CNTs network promotes the improvement of the electrode conductivity. D-AF exhibits more stable service life and stronger rate ability, compared with the copper foil. The reversible capacity of the cell with the D-AF electrode remains 789.55 mAh g−1, after 500 cycles at 1.0 C. It improves the cycle life and actual specific capacity of the battery, effectively. This work provides a new path for the development of flexible self-supported electrodes and the application of Multifunctional Silica in electrode.