A silicon-impregnated carbon nanotube mat as a lithium-ion cell anode

Abstract

Silicon is a widely-researched lithium ion (Li-Ion) battery anode material due to its high theoretical energy density of 4200 mAh g-1 , more than 10 times the specific capacity of conventional graphitic materials. However, silicon degrades rapidly as a lithium-storage material due to the volumetric changes that occur during cycling; these effects are welldocumented and necessitate the use of complicated or costly methods to ameliorate capacity loss. In lieu of these convoluted workarounds, this study presents a potential, novel silicon anode fabrication technique. In this original method, anode discs were fabricated by winding a carbon nanotube (CNT) felt and infiltrating it in-situ with an aqueous solution containing silicon nanoparticles and a hydroxypropyl guar binder. The resulting infiltrated felts were processed and constructed into coin cells and evaluated compared to conventional silicon-carbon black anodes. Samples had a large initial reversible capacity and promising rate capability performance. It is likely that the conductive CNT structure improves charge transfer properties while lessening the effects of volumetric expansion during lithiation. While there remains further work to be done, the results demonstrate that this novel anode fabrication method is viable and can be explored for further optimization.

Hierarchically structured silicon/graphene composites wrapped by interconnected carbon nanotube branches for lithium‐ion battery anodes

“…Moreover, the GCD profiles were not significantly distorted even at a high rate of 12,600 mA g −1 and the discharge capacity is recovered up to 1,679 mAh g −1 . Furthermore, Figure 4E shows the higher rate performance of CNT@NiNP@Si/rGO at different current densities compared to SiCNT electrodes reported in previous works 43‐49 . These results confirm the superior rate capability and recoverability of CNT@NiNP@Si/rGO electrode.…”

“…This capacity retention at 250th cycle was greater than most of the previous SiCNT based composite electrodes (Table 1). 33,43,47‐49,51 In addition, the low‐capacity performance of CNT@NiNP@rGO confirms that NiNP and carbon structure does not contribute to high capacity, but that it greatly improves the electrochemical performances of CNT@NiNP@Si/rGO by facilitating fast Li‐ion and electron transport and by buffering volume expansion of Si particles.…”

Distribution Uniformity of Water-Based Binders in Si Anodes and the Distribution Effects on Cell Performance

“…Figure compares the rate capabilities of the two cells made of electrodes with SBR/CMC and CMC; note that the cells have been activated by two cycles prior to the measurement. Because the cells have been activated, a sloping voltage plateau, representing the lithiation process of amorphous Si, , is obtained for all the discharging profiles in Figure a,b. For the cell made of the electrode with CMC in Figure a, the discharge capacities were 3033, 2676, 2312, and 1426 mAh g –1 at 0.1, 0.2, 0.4, and 0.8 C, respectively.…”

High Electrochemical Performance Silicon Thin-Film Free-Standing Electrodes Based on Buckypaper for Flexible Lithium-Ion Batteries

“…In this case, significant amounts of electrolytes and Li are consumed, and the distance of Li-ion diffusion is increased, resulting in a low Coulombic efficiency and material degradation [ 8 ]. Current methods of counteracting the aforementioned disadvantages associated with Si include the usage of Si nanowires, elaborate porous structures, and intricate C–Si composite structures [ 9 ]. CNTs are endowed with various useful properties, including a high aspect ratio, channels for lithium-ion intercalation, and excellent conductivity (electrical and thermal) [ 10 ].…”