Hierarchical Ni–Co Hydroxide Petals on Mechanically Robust Graphene Petal Foam for High‐Energy Asymmetric Supercapacitors

A hierarchical structure consisting of Ni–Co hydroxide nanopetals (NCHPs) grown on a thin free-standing graphene petal foam (GPF) has been designed and fabricated by a two-step process for pseudocapacitive electrode applications. The mechanical behavior of GPFs has been, for the first time to our knowledge, quantitatively measured from in situ scanning electron microscope characterization of the petal foams during in-plane compression and bending processes. The Young's modulus of a typical GPF is 3.42 GPa, indicating its outstanding mechanical robustness as a nanotemplate. The GPF/NCHP electrodes exhibit volumetric capacitances as high as 765 F cm−3, equivalent to an areal capacitance of 15.3 F cm−2 and high rate capability. To assess practical functionality, two-terminal asymmetric solid-state supercapacitors with 3D GPF/NCHPs as positive electrodes are fabricated and shown to exhibit outstanding energy and power densities, with maximum average energy density of ≈10 mWh cm−3 and maximum power density of ≈3 W cm−3, high rate capability (a capacitance retention of ≈60% at 100 mA cm−2), and excellent long-term cyclic stability (full capacitance retention over 15 000 cycles).

[1]  T. Mallouk,et al.  A Facile and Template-Free Hydrothermal Synthesis of Mn3O4 Nanorods on Graphene Sheets for Supercapacitor Electrodes with Long Cycle Stability , 2012 .

[2]  Zhenxing Zhang,et al.  Freestanding three-dimensional graphene/MnO2 composite networks as ultralight and flexible supercapacitor electrodes. , 2013, ACS nano.

[3]  K. Cen,et al.  Emerging energy and environmental applications of vertically-oriented graphenes. , 2015, Chemical Society reviews.

[4]  Pedro P. Irazoqui,et al.  Graphitic Petal Electrodes for All‐Solid‐State Flexible Supercapacitors , 2014 .

[5]  H.Q. Li,et al.  Ordered Whiskerlike Polyaniline Grown on the Surface of Mesoporous Carbon and Its Electrochemical Capacitance Performance , 2006 .

[6]  Jiaoyang Li,et al.  Ultrathin Mesoporous NiCo2O4 Nanosheets Supported on Ni Foam as Advanced Electrodes for Supercapacitors , 2012 .

[7]  R. Ruoff,et al.  High‐Volumetric Performance Aligned Nano‐Porous Microwave Exfoliated Graphite Oxide‐based Electrochemical Capacitors , 2013, Advanced materials.

[8]  B. Dunn,et al.  Pseudocapacitive oxide materials for high-rate electrochemical energy storage , 2014 .

[9]  S. Jun,et al.  High-performance supercapacitor electrode based on a polyaniline nanofibers/3D graphene framework as an efficient charge transporter , 2014 .

[10]  G. Lu,et al.  Fabrication of Graphene/Polyaniline Composite Paper via In Situ Anodic Electropolymerization for High-Performance Flexible Electrode. , 2009, ACS nano.

[11]  Pierre-Louis Taberna,et al.  Continuous carbide-derived carbon films with high volumetric capacitance , 2011 .

[12]  Chananate Uthaisar,et al.  Edge effects on the characteristics of li diffusion in graphene. , 2010, Nano letters.

[13]  Yury Gogotsi,et al.  Flexible MXene/Carbon Nanotube Composite Paper with High Volumetric Capacitance , 2015, Advanced materials.

[14]  Chang Liu,et al.  Advanced Materials for Energy Storage , 2010, Advanced materials.

[15]  Andreas Züttel,et al.  Investigation of electrochemical double-layer (ECDL) capacitors electrodes based on carbon nanotubes and activated carbon materials , 2003 .

[16]  Hao Jiang,et al.  Hierarchical self-assembly of ultrathin nickel hydroxide nanoflakes for high-performance supercapacitors , 2011 .

[17]  Shailesh Kumar,et al.  Structure‐Controlled, Vertical Graphene‐Based, Binder‐Free Electrodes from Plasma‐Reformed Butter Enhance Supercapacitor Performance , 2013 .

[18]  Dingshan Yu,et al.  Controlled Functionalization of Carbonaceous Fibers for Asymmetric Solid‐State Micro‐Supercapacitors with High Volumetric Energy Density , 2014, Advanced materials.

[19]  K. Cen,et al.  Molecular Insights into Aqueous NaCl Electrolytes Confined within Vertically-oriented Graphenes , 2015, Scientific Reports.

[20]  N. Motta,et al.  High performance solid-state supercapacitors based on compressed graphene foam , 2015 .

[21]  J. Tu,et al.  Graphene sheet/porous NiO hybrid film for supercapacitor applications. , 2011, Chemistry.

[22]  Cuimei Zhao,et al.  Synthesis of Co(OH) 2 /graphene/Ni foam nano-electrodes with excellent pseudocapacitive behavior and high cycling stability for supercapacitors , 2012 .

[23]  Z. Xia,et al.  X-ray diffraction patterns of graphite and turbostratic carbon , 2007 .

[24]  Jiangtian Li,et al.  Nanostructured carbon-metal oxide composite electrodes for supercapacitors: a review. , 2013, Nanoscale.

[25]  Cuimei Zhao,et al.  Electrodeposited Ni(OH)2 nanoflakes on graphite nanosheets prepared by plasma-enhanced chemical vapor deposition for supercapacitor electrode , 2012 .

[26]  T. Fisher,et al.  Plasma-grown graphene petals templating Ni–Co–Mn hydroxide nanoneedles for high-rate and long-cycle-life pseudocapacitive electrodes , 2015 .

[27]  Juan Li,et al.  Synthesis and electrochemical capacitance of mesoporous Co(OH)2 , 2007 .

[28]  T. Fisher,et al.  Controlled thin graphitic petal growth on oxidized silicon , 2012 .

[29]  Vinay Gupta,et al.  Potentiostatically deposited nanostructured CoxNi1−x layered double hydroxides as electrode materials for redox-supercapacitors , 2008 .

[30]  Dingshan Yu,et al.  Ternary Hybrids of Amorphous Nickel Hydroxide–Carbon Nanotube‐Conducting Polymer for Supercapacitors with High Energy Density, Excellent Rate Capability, and Long Cycle Life , 2015 .

[31]  T. Fisher,et al.  Mechanically robust honeycomb graphene aerogel multifunctional polymer composites , 2015 .

[32]  Yihong Wu,et al.  Fabrication of a Class of Nanostructured Materials Using Carbon Nanowalls as the Templates , 2002 .

[33]  Zexiang Shen,et al.  High-performance flexible asymmetric supercapacitors based on a new graphene foam/carbon nanotube hybrid film , 2014 .

[34]  Wei Huang,et al.  Hybrid structure of zinc oxide nanorods and three dimensional graphene foam for supercapacitor and electrochemical sensor applications , 2012 .

[35]  John R. Miller,et al.  Graphene Double-Layer Capacitor with ac Line-Filtering Performance , 2010, Science.

[36]  Peihua Huang,et al.  Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon. , 2010, Nature nanotechnology.

[37]  Hui‐Ming Cheng,et al.  Three-dimensional flexible and conductive interconnected graphene networks grown by chemical vapour deposition. , 2011, Nature materials.

[38]  Hui Tian,et al.  Carbon nanosheets as the electrode material in supercapacitors , 2009 .

[39]  Chi Cheng,et al.  Liquid-Mediated Dense Integration of Graphene Materials for Compact Capacitive Energy Storage , 2013, Science.

[40]  Meilin Liu,et al.  Nickel-cobalt hydroxide nanosheets coated on NiCo2O4 nanowires grown on carbon fiber paper for high-performance pseudocapacitors. , 2013, Nano letters.

[41]  Y. Gogotsi,et al.  True Performance Metrics in Electrochemical Energy Storage , 2011, Science.

[42]  Zhiyi Lu,et al.  Hierarchical Ni0.25Co0.75(OH)2 nanoarrays for a high-performance supercapacitor electrode prepared by an in situ conversion process , 2013 .

[43]  R. Petrov,et al.  Initial stages of few-layer graphene growth by microwave plasma-enhanced chemical vapour deposition , 2010, Nanotechnology.

[44]  A. Benayad,et al.  Synthesis of Chemically Bonded Graphene/Carbon Nanotube Composites and their Application in Large Volumetric Capacitance Supercapacitors , 2013, Advanced materials.

[45]  Huanwen Wang,et al.  Growing nickel cobaltite nanowires and nanosheets on carbon cloth with different pseudocapacitive performance. , 2013, ACS applied materials & interfaces.

[46]  X. Lou,et al.  General Solution Growth of Mesoporous NiCo2O4 Nanosheets on Various Conductive Substrates as High‐Performance Electrodes for Supercapacitors , 2013, Advanced materials.

[47]  Koen Schouteden,et al.  Synthesis of few-layer graphene via microwave plasma-enhanced chemical vapour deposition , 2008, Nanotechnology.

[48]  Pedro P. Irazoqui,et al.  A Review of Graphene‐Based Electrochemical Microsupercapacitors , 2014 .

[49]  T. Fisher,et al.  Synthesis of Porous Ni–Co–Mn Oxide Nanoneedles and the Temperature Dependence of Their Pseudocapacitive Behavior , 2015, Front. Energy Res..

[50]  Mashkoor Ahmad,et al.  Facile synthesis of single-crystal mesoporous CoNiO2 nanosheets assembled flowers as anode materials for lithium-ion batteries , 2014 .

[51]  John R Miller,et al.  Valuing Reversible Energy Storage , 2012, Science.

[52]  Timothy S. Fisher,et al.  MnO2-coated graphitic petals for supercapacitor electrodes , 2013 .

[53]  Y. Gogotsi,et al.  Materials for electrochemical capacitors. , 2008, Nature materials.

[54]  Xuan Zhang,et al.  Controllable synthesis of 3D NiχCo1−χ oxides with different morphologies for high-capacity supercapacitors , 2013 .

[55]  T. Wen,et al.  Synthesis of graphene-based nanomaterials and their application in energy-related and environmental-related areas , 2012 .

[56]  P. Irazoqui,et al.  Graphitic Petal Micro‐Supercapacitor Electrodes for Ultra‐High Power Density , 2014 .

[57]  Jan Ma,et al.  Surfactant-assisted electrochemical deposition of α-cobalt hydroxide for supercapacitors , 2011 .

[58]  Meryl D. Stoller,et al.  Review of Best Practice Methods for Determining an Electrode Material's Performance for Ultracapacitors , 2010 .

[59]  Yang Li,et al.  Nanoporous Ni(OH)2 thin film on 3D Ultrathin-graphite foam for asymmetric supercapacitor. , 2013, ACS nano.

[60]  M. Chan-Park,et al.  3D graphene-cobalt oxide electrode for high-performance supercapacitor and enzymeless glucose detection. , 2012, ACS nano.

[61]  Taihong Wang,et al.  Ultrathin porous NiCo2O4 nanosheet arrays on flexible carbon fabric for high-performance supercapacitors. , 2013, ACS applied materials & interfaces.

[62]  Guangwu Yang,et al.  Electrodeposited nickel hydroxide on nickel foam with ultrahigh capacitance. , 2008, Chemical communications.

[63]  Pooi See Lee,et al.  Enhancing electrochemical reaction sites in nickel-cobalt layered double hydroxides on zinc tin oxide nanowires: a hybrid material for an asymmetric supercapacitor device. , 2012, Nanoscale.

[64]  G. R. Rao,et al.  Ultralayered Co3O4 for High-Performance Supercapacitor Applications , 2011 .

[65]  Zhen Zhou,et al.  Preparation and electrochemical performances of doughnut-like Ni(OH)₂-Co(OH)₂ composites as pseudocapacitor materials. , 2012, Nanoscale.