Scalable one-step production of electrochemically exfoliated graphene decorated with transition metal oxides for high-performance supercapacitors

• Published in: Nanoscale 2021-10, Vol.13 (37), p.15859-15868
• Main Authors: Romaní Vázquez, Adrián, Neumann, Christof, Borrelli, Mino, Shi, Huanhuan, Kluge, Matthias, Abdel-Haq, Wajdi, Lohe, Martin R, Gröber, Carsten, Röpert, Andreas, Turchanin, Andrey, Yang, Sheng, Shaygan Nia, Ali, Feng, Xinliang
• Format: Article
• Language: English
• Subjects: Capacitance; Continuous flow; Graphene; Iron; Manganese; Production methods; Supercapacitors; Titanium; Transition metal compounds; Transition metal oxides; Two dimensional materials
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d1nr03960a

Graphene and related materials have been widely studied due to their superior properties in a wide range of applications. However, large-scale production remains a critical challenge to enable commercial acceptance. Here, we present a facile, scalable, one-step electrochemical method for producing hybrid transition metal oxide (V, Fe, Ti, or Mn)/graphene materials (TMO-EGs) as active materials for supercapacitors. Therein, we have designed and developed a continuous flow reactor with a high production rate (>4 g h −1 ) of TMO-EGs, where the TMO accounts for 36 weight%. TMO-EG flakes demonstrate a moderate lateral size of up to 5 μm and a specific surface area of 64 m 2 g −1 . Notably, TMO-EGs present a capacitance of up to 188 F g −1 as single electrodes in 4 M LiCl. The most promising material, MnO x -EG, has been used for the large-scale production of thin-film supercapacitor devices (40 × 40 × 0.25 mm) in a commercial pilot line. Using 1 M Na 2 SO 4 as the electrolyte, the as-fabricated devices deliver a capacitance of 52 mF cm −2 , with 83% capacitance retention after 6000 charge-discharge cycles, comparable to recent reports of similar devices. The simplicity, scalability, and versatility of our method are highly promising to promote the commercial applications of graphene-based materials and can be further developed for the upscalable production of other 2D materials, such as transition metal dichalcogenides and MXenes. One-step in situ functionalization/electrochemical exfoliation in an innovative continuous-flow reactor enables the large-scale production of active materials for the fabrication of high performance thin-film supercapacitors.