Author’s Accepted Manuscript A gradient bi-functional graphene-based modified electrode for vanadium redox flow batteries Guangjian Hu, Minghua Jing, Da-Wei Wang, Zhenhua Sun, Chuan Xu, Wencai Ren, Hui-Ming Cheng, Chuanwei Yan, Xinzhuang Fan, Feng Li PII: S2405-8297(17)30661-X DOI: https://doi.org/10.1016/j.ensm.2017.12.026 Reference: ENSM282 To appear in: Energy Storage Materials Received date: 1 December 2017 Revised date: 23 December 2017 Accepted date: 24 December 2017 Cite this article as: Guangjian Hu, Minghua Jing, Da-Wei Wang, Zhenhua Sun, Chuan Xu, Wencai Ren, Hui-Ming Cheng, Chuanwei Yan, Xinzhuang Fan and Feng Li, A gradient bi-functional graphene-based modified electrode for vanadium redox flow batteries, Energy Storage Materials, https://doi.org/10.1016/j.ensm.2017.12.026 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. www.elsevier.com/locate/ensm