Sustainable Production of Graphene from Solar‐Driven Expanded Graphite

Scalable synthesis of graphene sheets is challenging due to the complex production processes. Few‐layered graphene sheets with high lateral sizes (4–5 μm) through a state‐of‐the‐art solar irradiation‐driven liquid‐phase exfoliation technique are achieved. The sunlight is directly used on the intercalated graphite flakes for just 0.5 s to achieve the graphite expansion. Using focused sunlight makes our solar expansion technique sustainable with zero energy demand (0 J). The total energy spent to produce 1 kg of graphene through this technique is only around 2.135 MJ. The produced graphene sheets show significant electrical conductivity (1586 S cm −1 ) and high in‐plane thermal conductivity (196.3 W mK −1 ). The electromagnetic interference (EMI) shielding properties of solar graphene are evaluated in the X‐band region, and it shows a very high shielding effectiveness of about 71.5 dB at a thickness of ≈80 μm with an absolute EMI shielding effectiveness of about 11983.7 dB cm 2 g −1 . Overall, this work provides a viable approach for the efficient, scalable production of graphene with reduced energy consumption and cost, contributing to the sustainable production of graphene.