Multilayer Silicene Nanosheets Derived from a Recycling Process Using End-of-Life Solar Cells Producing a Silicene/Graphite Composite for Anodes in Lithium-Ion Batteries

Abstract

Silicene, with its unique two-dimensional layered Si nanosheets, has been attracting increasing attention in recent years. This is due to its graphene-like structure and outstanding anode properties. There have been a few experimental studies of anodes in lithium-ion batteries (LIBs). The main problems are limited material resources and complicated production methods, which limit their practical applications. Therefore, large-scale and high-quality fabrication of silicene using green methods and sustainable material sources is currently an urgent challenge, especially for commercial applications. In this work, we fabricated a multilayer silicene derived from end-of-life silicon solar cells using chemical activation and exfoliation processes. Most of synthesized silicene sheets are multilayered with typical thicknesses between 1.73 to 3 nm. Then, they were employed as anode materials in LIBs. The silicene/graphite composite shows a stable reversible capacity of ∼290 mAh g–1 at a current density of 1C after 500 cycles. This anode had a Coulombic efficiency above 97% and a greater than 93% capacity retention. Our composite material shows good integration in a single system, leading to improved capacity and enhanced stability. To the best of our knowledge, this is the first time that a recycling process for solar waste has been used to produce material for fabrication of multilayer silicene that can be used as an anode material in LIBs. Furthermore, this work also provides a new opportunity in material recycling to produce silicene for fast-charging batteries, given the ever-growing number of EVs and for a more sustainable energy future.

Beyond the horizons of graphene: xenes for energy applications

“…Yutthanakon et al reported a chemical exfoliation technique to produce 1.73–3 nm thick silicene via a relatively greener route. 63 As shown in Fig. 21, they observed a 306 mA h g −1 discharge capacity at 1C (the amount of electrical current that goes through the battery divided by the area of its layer) rate and approximately 290 mA h g −1 at 1C current density after 500 cycles with 97% retention.…”

“…This result showed that silicene is semi-metallic. 63 Due to its buckling structure, the thermal conductivity of silicene is much lower than that of graphene. As a result, silicene shows great potential for application in thermoelectric devices.…”

“…21, they observed a 306 mA h g −1 discharge capacity at 1C (the amount of electrical current that goes through the battery divided by the area of its layer) rate and approximately 290 mA h g −1 at 1C current density after 500 cycles with 97% retention. 63 Furthermore, the CV curves in Fig. 21d show two sets of sharp peaks at ∼0.06 V and ∼0.15 V, corresponding to lithium-ion intercalation and deintercalation in the silicene–graphene anode, respectively.…”