ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Preparation of graphene by electrochemical exfoliation in Na₂SO₄ solution

Min Chen, Aimin Liu, Lingyu Kong, Fengguo Liu, Song Li, Yubao Liu, and Zhongning Shi

Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, China

E-mail: liuam@smm.neu.edu.cn

Received: 20 September 2024  Accepted: 14 August 2025

Abstract:

Graphene has been widely studied due to its unique structure and exceptional performance. Various methods are available for preparing graphene, and the electrochemical exfoliation method is chosen for its environmentally friendly, ease of operation, and strong controllability. However, the process of electrochemical exfoliation preparation is influenced by various factors, which still shows challenges of slow exfoliation speed and low yield. In this study, high-purity flexible graphite paper and a saturated calomel electrode (SCE) were used as a three-electrode system, using yield, interlayer spacing, and defect degree as evaluation criteria to explore the influence of electrolytic voltage and electrolyte concentration on graphite electrochemical exfoliation. Using dispersion state, settling time, and defect degree as evaluation criteria to examined the impact of dispersant type on the quality of graphene. The research demonstrated that electrochemical exfoliating at 10 V cell voltage with a bipolar distance of 2 cm in a 0.20 M Na₂SO₄ solution at pH 7 and room temperature, followed by a 10 min ultrasound dispersion in a C₂H₅OH medium at a liquid–solid ratio of 1444:1. The efficiency of graphene production is 59.8%, with low defect levels (I_D/I_G = 0.355), large interlayer spacing (d = 0.350 nm), and a few layers (approximately 4 layers). In addition, the graphene dispersed in a N,N-Dimethylformamide (DMF) medium with a liquid–solid ratio of 1512:1 exhibits the highest level of stability.

Keywords: Graphene; Electrochemical exfoliation; Preparation; Graphite paper; Quality of graphene

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04328-6

Chemical Papers 79 (12) 8491–8504 (2025)