Facile synthesis of few-layer graphene from biomass waste and its application in lithium ion batteries

• A facile and novel approach for the preparation of few-layer graphene.
• The process is simple, eco-friendly, cost-effective, and highly efficient.
• The resulting few-layer graphene sheets show many favorable features.
• The few-layer graphene anode exhibits superior electrochemical properties.

Graphene is an appealing two-dimensional material with superior mechanical, electrical, and thermal properties. Mass production of high-quality graphene is attracting more and more researchers' attention in recent years. Most of the current methods for synthesizing graphene use purified chemical reagents that could be expensive for large-scale production. In this study, we have developed a less expensive method to synthesise high-quality graphene sheets from wheat straw via a combined hydrothermal and graphitization approach. The resulting graphene sheets show favorable features such as ultrathin nanosheet frameworks (2–10 atomic layers), high graphitization (up to 90.7%), graphite-like interlayer spacing (0.3362 nm), and the mesoporous structure. When used as an anode material for lithium ion batteries, the few-layer graphene delivers high reversible capacity (502 mAh g− 1 at 0.1 C), superior rate capability (463.5, 431.4, and 306.8 mAh g− 1 at 1, 2, and 5 C, respectively), and good cycling performance (392.8 mAh g− 1 at 1 C after 300 cycles). The wheat straw-derived graphene sheets also display the relatively flat voltage profiles with a negligible charge/discharge voltage hysteresis. Moreover, this low-cost, highly efficient, and catalyst-free technique is a significant milepost towards environmentally-sustainable, commercially feasible fabrication of carbon nanomaterials from renewable natural resources.

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