One-pot synthesis of manganese oxide/graphene composites via a plasma-enhanced electrochemical exfoliation process for supercapacitors
Dang Nhat Minh, Thanh Hai Nguyen, To Van Nguyen, Tran Viet Thu, Le Tuan Anh Hoang, Masashi Akabori, Nobuaki Ito, Nguyen Hai Yen, Trong Lu Le, Tuan Hong Nguyen, Thao V. Nguyen, Phan Ngoc Hong
Abstract
Abstract In this work, a feasible one-pot approach to synthesize manganese oxide/graphene composites, the so-called plasma-enhanced electrochemical exfoliation process (PE 3 P), has been developed. Herein, a composite of graphene decorated with manganese oxide nanoparticles was prepared via PE 3 P from a KMnO 4 solution and graphite electrode under a voltage of 70 V in an ambient environment. By controlling the initial KMnO 4 concentration, we obtained distinct MnO 2 /graphene samples. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy. The electrochemical measurements of the MnO 2 /graphene composites revealed that the specific capacitance of the samples is approximately 320 F g –1 at a scan rate of 10 mV s –1 , which is comparably very high for manganese oxide/carbon-based supercapacitor electrode materials. Considering the simple, low-cost, one-step and environmentally friendly preparation, our approach has the potential to be used for the fabrication of MnO 2 /graphene composites as the electrode materials of supercapacitors.