title: Single-Nanowire Electrochemical Probe Detection for Internally Optimized Mechanism of Porous Graphene in Electrochemical Devices.
abstract: Graphene has been widely used to enhance the performance of energy storage devices due to its high conductivity, large surface area, and excellent mechanical flexibility. However, it is still unclear how graphene influences the electrochemical performance and reaction mechanisms of electrode materials. The single-nanowire electrochemical probe is an effective tool to explore the intrinsic mechanisms of the electrochemical reactions in situ. Here, pure MnO2 nanowires, reduced graphene oxide/MnO2 wire-in-scroll nanowires, and porous graphene oxide/MnO2 wire-in-scroll nanowires are employed to investigate the capacitance, ion diffusion coefficient, and charge storage mechanisms in single-nanowire electrochemical devices. The porous graphene oxide/MnO2 wire-in-scroll nanowire delivers an areal capacitance of 104 nF/μm(2), which is 4.0 and 2.8 times as high as those of reduced graphene oxide/MnO2 wire-in-scroll nanowire and MnO2 nanowire, respectively, at a scan rate of 20 mV/s. It is demonstrated that the reduced graphene oxide wrapping around the MnO2 nanowire greatly increases the electronic conductivity of the active materials, but decreases the ion diffusion coefficient because of the shielding effect of graphene. By creating pores in the graphene, the ion diffusion coefficient is recovered without degradation of the electron transport rate, which significantly improves the capacitance. Such single-nanowire electrochemical probes, which can detect electrochemical processes and behavior in situ, can also be fabricated with other active materials for energy storage and other applications in related fields.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Mengyu
authors.initials: M
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Xuanpeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Han
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Liang
authors.initials: L
authors.lastname: He
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Chaojiang
authors.initials: C
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Kangning
authors.initials: K
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Xiaocong
authors.initials: X
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Qiulong
authors.initials: Q
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Zijia
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Mai
mesh_terms: D025802:Electric Capacitance; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004579:Electron Transport; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D017895:Manganese Compounds / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry*; D016062:Porosity
chemical_list: D007477:Ions; D017895:Manganese Compounds; D010087:Oxides; D006108:Graphite; C016552:manganese dioxide
keywords: Porous graphene oxide; electron transport; intercalation capacitance; ion transport; nanowire