Graphene Platforms for Smart Energy Generation and Storage Minghui Ye, Zhipan Zhang, Yang Zhao, Liangti Qu  Joule  Volume 2, Issue 2, Pages 245-268 (February 2018) DOI: 10.1016/j.joule.2017.11.011 Copyright © 2017 Elsevier Inc. Terms and Conditions

Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 1 The Progress in Tailoring the Properties of Graphene (A) Microscopic structure modification of graphene, including GQDs (reprinted from Gao et al.,43 with permission. Copyright 2012, American Chemical Society), GNRs (reprinted from Tour et al.,44 with permission. Copyright 2009, Nature Publishing Group), GNM (reprinted from Nam et al.,47 with permission. Copyright 2016, Royal Society of Chemistry). (B) Functionalized graphene mainly comprises heteroatom-doped graphene and graphene hybrids. Reprinted from Qu et al.,66 with permission. Copyright 2017, American Chemical Society. (C) Self-assembly of graphene, where 1D graphene fibers/microtubules, 2D graphene films, and 3D ultralight graphene frameworks have been successfully fabricated. Reprinted from Qu et al.,67 with permission. Copyright 2013, Wiley-VCH; reprinted from Qu et al.,68 with permission. Copyright 2012, American Chemical Society; reprinted from Qu et al.,69,70 with permission. Copyright 2014, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 2 Graphene-Based CPEhs in Response to Moisture (A) Demonstration of the mechanism of power generation. (B) Voltage output of the CPEh in response to variation in RH. (C) Schematic illustration of an encapsulated CPEh cell. (D) Four g-GOF-based CPEhs assembled in series can light up an LED with moisture (RH = 80%). Reprinted from Qu et al.,115 with permission. Copyright 2016, Royal Society of Chemistry. (E) GOR-NM with abundant oxygen-containing functional groups and widely distributed nanopores. Reprinted from Qu et al.,117 with permission. Copyright 2017, Wiley-VCH. (F) 1D graphene fiber power generator with an alternative RGO/g-GO/RGO structure. Reprinted from Qu et al.,118 with permission. Copyright 2017, Elsevier. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 3 Monolayer Graphene-Based Electric Generators in Response to Liquid Flow (A) A droplet of 0.6 M NaCl solution was sandwiched between graphene and a SiO2/Si wafer, and then drawn by the wafer at certain velocities. (B) Left: DFT results for the distribution of differential charge near monolayer graphene caused by adsorbing one to three rows of hydrated sodium cations, and the corresponding adsorption energy (Ea). Upper right: schematic illustration of the pseudocapacitance formed by a static droplet on graphene. Lower right: schematic illustration of the potential difference induced by a moving droplet. Reprinted from Guo et al.,124 with permission. Copyright 2014, Nature Publishing Group. (C) Schematic illustration of a waving potential by moving the graphene sample on a polyester terephthalate (PET) substrate vertically across the water surface within a container. (D) Typical voltage signals produced as a sample were inserted and pulled out of 0.6 M NaCl solution at a velocity of 3.1 cm s−1. (E) Charge redistribution of graphene upon adsorption of hydrated Na+ (red for regions with charge accumulation and blue for charge depletion). Lower right inset: Hall voltages as functions of the magnetic field for graphene immersed in deionized water and 1 mM NaCl. (F) Schematic EDL and its boundaries by ion adsorption (left) and desorption (right) on the surface of graphene during the insertion and pulling out processes, respectively. The potential difference induced and the hole concentration gradient in the graphene sheet are also illustrated. Reprinted from Guo et al.,125 with permission. Copyright 2014, Nature Publishing Group. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 4 Macroscopic GHM/GF-Based Electric Generators in Response to Liquid Flow (A) Schematic illustration of the experimental setup of hydraulic-electric energy conversion with the GHM. (B) When a continuous electrolyte (0.1 M NaCl) flowed across GHM driven by a gas pressure difference of 5 kPa, a remarkable ionic current of ∼2,200 pA was obtained. (C) Working mechanism for the generation of streaming current. Reprinted from Jiang et al.,121 with permission. Copyright 2013, Wiley-VCH. (D) Schematic layout of the flow test facility, in which water flowed through 3D-GF at a certain velocity. (E) Current output of 3D-GF under different flow velocities. Reprinted from Sun et al.,122 with permission. Copyright 2014, Royal Society of Chemistry. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 5 Graphene-Based Power Generation in Response to Friction Force (A) Schematic illustration of energy harvesters based on the triboelectric effect. Reprinted from Kim et al.,126 with permission. Copyright 2016, Royal Society of Chemistry. (B) The structure of G-TEG. (C) Output current from nL-G-TEG. (D−G) Power generation mechanism of G-TEG, including press (D), release (E), equilibrium (F), and re-press (G) process. Reprinted from Kim et al.,127 with permission. Copyright 2014, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 6 Graphene-Based Power Generation in Response to Pressure Force (A) Energy generation based on the piezoelectric effect. Reprinted from Kim et al.,126 with permission. Copyright 2016, Royal Society of Chemistry. (B) The architecture of G-PEG. (C and D) The output voltages were measured under switching polarity, which meant the electric potential distributions were similar to bending G-PEG downward (C) or upward (D). (E) Power generation mechanism of a piezoelectric PVDF fibers in G-PEG. Reprinted from Liu et al.,128 with permission. Copyright 2016, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 7 Graphene-Based Power Generation in Response to Heat (A) Schematic illustration of energy generation based on the thermoelectric effect. Reprinted from Kim et al.,126 with permission. Copyright 2016, Royal Society of Chemistry. (B) The structure of graphene-based TNG. (C) Temperature dependence of electrical conductivity (σ) for the epitaxial BST/graphene thin-film and BST film. Reprinted from Kim et al.,131 with permission. Copyright 2017, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 8 Graphene-Based Flexible LIB and Stretchable NIB (A) Schematic of a flexible battery. (B) Scanning emission microscopy images showed the 3D interlinked structure of LTO/GF. (C) The LFP/GF and LTO/GF full battery possessed good flexibility and could light up a red LED under bending. (D and E) Galvanostatic charging/discharging curves (D) and specific capacities (E) of the as-fabricated battery at flat and bent states. Reprinted from Cheng et al.,137 with permission. Copyright 2012, US National Academy of Sciences. (F) Schematic illustration of the stretchable NIB. (G) Digital photographs showing the full battery at a strain of 20% and 50%. (H) The charge-discharge curves of the stretchable NIB in the unstretched and stretched states (1C = 100 mA g−1). Reprinted from Yu et al.,139 with permission. Copyright 2017, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 9 Graphene-Based, 3D-Printed Microbatteries (A) Schematic of the preparation of 3D-printed interdigitated electrodes. (B and C) Digital images showing the syringes loading LFP/GO and LTO/GO inks (B) and the interdigitated electrodes (C). (D) Cycling stability of the 3D-printed full cell. Reprinted from Hu et al.,143 with permission. Copyright 2016, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 10 Graphene-Based Smart Batteries in Response to Pressure and Moisture (A and B) Schematic structure (A) and working principle (B) of the responsive ZAB under compression. (C) Self-regulated voltage output of ZAB under various compressive strains. (D) Dynamic response of voltage output based on the input pressure at 4, 8, 16, and 32 times per unit of 50 s. Reprinted from Qu et al.,144 with permission. Copyright 2016, Wiley-VCH. (E–G) Schematic illustration of the electrochemical reaction of the Li-GOF battery after adsorbing H2O (E). The Li-GOF battery was placed beneath the nose of a person to detect breathing (F) or in front of the mouth to monitor the blow (G). Reprinted from Qu et al.,145 with permission. Copyright 2016, Royal Society of Chemistry. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 11 Graphene-Based Self-Healing SC and Electrochromic MSC (A) Schematic diagrams of the structure of a self-healing SC. (B) The self-healable mechanism. Reprinted from Gao et al.,146 with permission. Copyright 2017, American Chemical Society. (C) Schematic fabrication of SR-MSC. (D) Digital photos of SR-MSCs on a flexible PET substrate. (E) The electrochromic mechanism of viologen. (F) Photographs of the reversible electrochromic effect of SR-MSC during charge-discharge cycles. Reprinted from Feng et al.,147 with permission. Copyright 2017, Wiley-VCH. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 12 Graphene-Based Integrated SC (A) Scheme illustrating the production process of a direct-spinning SC. (B and C) Photo (B) and scanning emission spectroscopy (SEM) image (C) of an RGO/ACa-PVA/RGO fiber SC. Reprinted from Qu et al.,150 with permission. Copyright 2016, Royal Society of Chemistry. (D) Schematic of the laser reduction of GO fiber into RGO-GO-RGO fiber. (E and F) SEM image of the RGO/GO/RGO fiber (E) and the corresponding energy-dispersive X-ray spectroscopy (F). Reprinted from Qu et al.,151 with permission. Copyright 2014, Royal Society of Chemistry. (G) The fabrication process of RGO/GO/RGO foam. (H) Digital photograph showing the excellent flexibility of the integrated SC. (I) Cross-section SEM image of RGO/GO/RGO foam. Reprinted from Qu et al.,152 with permission. Copyright 2017, Royal Society of Chemistry. Joule 2018 2, 245-268DOI: (10.1016/j.joule.2017.11.011) Copyright © 2017 Elsevier Inc. Terms and Conditions