Si1–xGex anode synthesis on plastic films for flexible rechargeable batteries

Abstract

SiGe is a promising anode material for replacing graphite in next generation thin-film batteries owing to its high theoretical charge/discharge capacity. Metal-induced layer exchange (LE) is a unique technique used for the low-temperature synthesis of SiGe layers on arbitrary substrates. Here, we demonstrate the synthesis of Si1−xGex (x = 0–1) layers on plastic films using Al-induced LE. The resulting SiGe layers exhibited high electrical conductivity (up to 1200 S cm−1), reflecting the self-organized doping effect of LE. Moreover, the Si1−xGex layer synthesized by the same process was adopted as the anode for the lithium-ion battery. All Si1−xGex anodes showed clear charge/discharge operation and high coulombic efficiency (≥ 97%) after 100 cycles. While the discharge capacities almost reflected the theoretical values at each x at 0.1 C, the capacity degradation with increasing current rate strongly depended on x. Si-rich samples exhibited high initial capacity and low capacity retention, while Ge-rich samples showed contrasting characteristics. In particular, the Si1−xGex layers with x ≥ 0.8 showed excellent current rate performance owing to their high electrical conductivity and low volume expansion, maintaining a high capacity (> 500 mAh g–1) even at a high current rate (10 C). Thus, we revealed the relationship between SiGe composition and anode characteristics for the SiGe layers formed by LE at low temperatures. These results will pave the way for the next generation of flexible batteries based on SiGe anodes.

Si‐Based High‐Entropy Anode for Lithium‐Ion Batteries

“…As a comparison, we also select Si-Ge alloy as the reference anode since it shows better capacity retention than pure Si. [43][44] After ball milling, the compounds have characteristic feature of secondary particles at several micrometers as shown in Figure S1 (Supporting Information). SEM-EDS mappings in Figure S2 (Supporting Information) confirm the homogeneous distribution of compositional elements in all the as-synthesized samples.…”

On the thermoelectric alloy SixGe1-x

“…SixGe1-x composites are wiedly used in thermogenerators, coolers, sensors, 1,2 thin-film transistors, 3 batteries, 4 solar cells, 5,6 photodetectors 7,8 and others. These alloys are good high-temperature materials for the temperature range up to 1200℃.…”

Thickness Dependency of Battery Anode Properties in Multilayer Graphene

“…However, performance degradation due to Li precipitation during the charge/discharge process remains an underlying issue . Si, which has been used as a semiconductor thin film, is promising as anode materials for thin-film batteries because of its large Li capacity in addition to being inexpensive and safe. − However, the large volume expansion during Li insertion significantly degrades cycle characteristics. From the viewpoint of stable operation, graphite is attracting attention again as an anode material, which has been used for current lithium-ion batteries (LIB) with liquid electrolytes.…”

“…The MLG growth temperature was lowered to 350 °C, especially in Ni, allowing for flexible thin-film battery anodes using plastic films . However, the thin (50 nm) MLG anode exhibited low capacity in the voltage plateau region, which could prevent stable voltage operation. , Conversely, the anode properties of Si-based materials synthesized by LE have been reported. , The thick (≥500 nm) films provided high capacities; however, they had issues with cycle characteristics. In this study, we investigated the effect of MLG thickness on anode properties toward the application of MLG in thin-film batteries.…”

“…28,29 Conversely, the anode properties of Si-based materials synthesized by LE have been reported. 4,5 The thick (≥500 nm) films provided high capacities; however, they had issues with cycle characteristics. In this study, we investigated the effect of MLG thickness on anode properties toward the application of MLG in thin-film batteries.…”