High Capacity, Reversible Silicon Thin-Film Anodes for Lithium-Ion Batteries

The influence of carrier density and doping type on lithium insertion and extraction processes at silicon surfaces

“…5(d) retains its integrity after 30 cycles apart from some surface roughening. As more Li + is inserted in to the n-type Si when compared to the p-type Si, a greater expansion and contraction of the n-type Si(100) during cycling occurs causing the cracking of the anode [22][23][24]. The observation of a volume expansion in n-type Si(100) suggests an anisotropic volume or phase change mechanism, which for amorphous Li-Si phases is known to be anisotropic [77], but it is not found in p-type Si(100) even though it is an identical crystal.…”

“…When bulk Si is fully lithiated to Li15Si4 it undergoes a volume expansion of ~280-300% and has a maximum theoretical volumetric capacity of 2190 mAh cm -3 . Unfortunately, Si electrodes pulverize due to this large expansion and contraction upon Li insertion and extraction and this causes the electrode material to lose contact with the current collector, resulting in a decrease in charge storage capacity over time [13,[19][20][21][22][23][24][25][26].…”

Li15Si4Formation in Silicon Thin Film Negative Electrodes

“…1 Acoustic emission studies and imaging techniques have indicated that this phase transition can result in high internal stresses, leading to particle fracture and cell fade. 2 To overcome the issues associated with Li 15 Si 4 phase formation and volume expansion during cycling, researchers have demonstrated high cycle life in Li cells by using Si in the form of nanoparticles, 3,4 nanowires, 5,6 nanopillars, 7,8 thin films, 9,10 and in alloys with inactive or active phases. 11,12 These studies have reported various threshold sizes for nanoparticles (150 nm), 3,4 nanowires (300 nm), 13 and amorphous thin films (2.5 μm), 14 below which Li 15 Si 4 formation does not occur.…”

Rationally Designed Silicon Nanostructures as Anode Material for Lithium‐Ion Batteries

“…[105] The film with the thickness of 250 nm behaved significantly initial lithiation capacity of approximately 4100 mAh g À1 and maintained a stable capacity retention of 3500 mAh g À1 after 30 cycles, which was superior to the 1 mm one. However, the sever creaking emerged on the surface of the thin film after charge/discharge processes (Figure 9c), attributed to the huge volume expansion and un-treated surface condition.…”