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Yan Jiang, Yue Wang, Dehong Zeng, Yao Wang, Yangde Ma, Hai Wang, Xin Zhang, Xiaoping Dai
Carbon is widely studied as an electrical double-layer capacitor (EDLC) electrode material due to its high specific surface area and good electronic conductivity. However, the low capacitance and energy density limit its further commercial applications. Herein, we report a facile and novel synthesis of dilute CoNi alloy nanoparticles embedded into ultramicroporous carbon (CoNi/UMCs) via a template-assisted strategy using SBA-15 as a template. The CoNi alloy serves as not only the electron collector to decrease the conductivity during tests, but also creates CoNi oxide/oxhydroxide on the alloy surface in an alkali solution, promoting redox reactions in pseudocapacitors, enhancing the performance of supercapacitors...
March 21, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
Farah Naeem, Sumayyah Naeem, Yuting Zhao, Dingrun Wang, Jing Zhang, YongFeng Mei, Gaoshan Huang
TiO2 is a promising environment friendly, low cost, and high electrochemical performance material. However, impediments like high internal ion resistance and low electrical conductivity restrict its applications as electrode for supercapacitor. In the present work, atomic layer deposition was used to fabricate TiO2 nanomembranes (NMs) with accurately controlled thicknesses. The TiO2 NMs were then used as electrodes for high-performance pseudocapacitors. Experimental results demonstrated that the TiO2 NM with 100 ALD cycles had the highest capacitance of 2332 F/g at 1 A/g with energy density of 81 Wh/kg...
March 13, 2019: Nanoscale Research Letters
Tae Gwang Yun, Minkyu Park, Dong-Ha Kim, Donghyuk Kim, Jun Young Cheong, Jin Gook Bae, Seung Min Han, Il-Doo Kim
Flexible-stretchable electrochromic-supercapacitor systems are widely considered as a promising multi-functional energy storage device that eliminates the need for an external power source. Nevertheless, the performance of conventional designs deteriorates significantly as a result of electrode/electrolyte exposure to atmosphere as well as mechanical deformations for the case of flexible systems. In this study, we suggest an all transparent-stretchable electrochromic-supercapacitor device with ultrastable performance, which is consisted of the Au/Ag core-shell nanowire embedded polydimethylsiloxane (PDMS), bi-stacked WO3 nanotube/PEDOT:PSS, and polyacrylamide (PAAm) based hydrogel electrolyte...
February 19, 2019: ACS Nano
Gang Wang, Steffen Oswald, Markus Löffler, Klaus Müllen, Xinliang Feng
Supercapacitors have aroused considerable attention due to their high power capability, which enables charge storage/output in minutes or even seconds. However, to achieve a high energy density in a supercapacitor has been a long-standing challenge. Here, graphite is reported as a high-energy alternative to the frequently used activated carbon (AC) cathode for supercapacitor application due to its unique Faradaic pseudocapacitive anion intercalation behavior. The graphite cathode manifests both higher gravimetric and volumetric energy density (498 Wh kg-1 and 431...
February 15, 2019: Advanced Materials
Tianyu Liu, Zhengping Zhou, Yichen Guo, Dong Guo, Guoliang Liu
High mass loading and fast charge transport are two crucial but often mutually exclusive characteristics of pseudocapacitors. On conventional carbon supports, high mass loadings inevitably lead to sluggish electron conduction and ion diffusion due to thick pseudocapacitive layers and clogged pores. Here we present a design principle of carbon supports, utilizing self-assembly and microphase-separation of block copolymers. We synthesize porous carbon fibers (PCFs) with uniform mesopores of 11.7 nm, which are partially filled with MnO2 of <2 nm in thickness...
February 8, 2019: Nature Communications
Chuangang Hu, Yi Lin, John W Connell, Hui-Ming Cheng, Yury Gogotsi, Maria-Magdalena Titirici, Liming Dai
Owing to their high earth-abundance, eco-friendliness, high electrical conductivity, large surface area, structure tunability at the atomic/morphological levels, and excellent stability in harsh conditions, carbon-based metal-free materials have become promising advanced electrode materials for high-performance pseudocapacitors and metal-air batteries. Furthermore, carbon-based nanomaterials with well-defined structures can function as green catalysts because of their efficiency in advanced oxidation processes to remove organics in air or from water, which reduces the cost for air/water purification and avoids cross-contamination by eliminating the release of heavy metals/metal ions...
January 28, 2019: Advanced Materials
Caleb Alexander, J Tyler Mefford, Jennette Saunders, Robin Forslund, Keith P Johnston, Keith J Stevenson
We have synthesized a library of perovskite oxides with the composition La1-xSrxBO3-δ (x = 0-1; B = Fe, Mn, Co) to systematically study anion-based pseudocapacitance. The electrochemical capacitance of these materials was evaluated by cyclic voltammetry and galvanostatic charging/discharging in 1 M KOH. We find that greater oxygen vacancy content (δ) upon systematic incorporation of Sr2+ linearly increases the surface-normalized pseudocapacitance with a slope controlled by the B-site element. La0.2Sr0.8MnO2...
January 14, 2019: ACS Applied Materials & Interfaces
Deepak P Dubal, Nilesh R Chodankar, Shizhang Qiao
Owing to the excellent physical properties of metal nitrides such as metallic conductivity and pseudocapacitance, they have recently attracted much attention as competitive materials for high-performance supercapacitors (SCs). However, the voltage window for metal nitride-based symmetric SCs is limited (0.6-0.8 V) in aqueous electrolyte due to the oxidation at high negative potentials. In this respect, ultra-small tungsten nitride particles onto the phosphorous modified carbon fabric (W2 N@P-CF) are engineered as a promising hybrid electrode for pseudocapacitors...
January 2019: Small
John B Cook, Terri C Lin, Hyung-Seok Kim, Andrew Siordia, Bruce S Dunn, Sarah H Tolbert
Pseudocapacitors with non-diffusion-limited charge storage mechanisms allow for fast kinetics that exceed conventional battery materials. It has been demonstrated that nanostructuring conventional battery materials can induce pseudocapacitive behavior. In our previous study, we found that assemblies of metallic 1T MoS2 nanocrystals show faster charge storage compared to the bulk material. Quantitative electrochemistry demonstrated that the current response is capacitive. In this work, we perform a series of operando X-ray diffraction studies upon electrochemical cycling to show that the high capacitive response of metallic 1T MoS2 nanocrystals is due to suppression of the standard first-order phase transition...
January 3, 2019: ACS Nano
Fei Lu, Min Zhou, Kun Su, Tao Ye, Yijun Yang, Tran Dai Lam, Yoshio Bando, Xi Wang
Spinel NiCo2X4 (X = O or S), comprising two geometrical cobalt ions: Co2+ in tetrahedral site (Co2+Td) and Co3+ in octahedral site (Co3+Oh), has widely evaluated as a promising pseudocapacitor electrode material. Previous literatures mainly demonstrated that much higher specific capacitance of NiCo2S4 than that of NiCo2O4 was ascribed to the higher electronic conductivity. However, we argue that only a small amount of capacitance can be induced by the electronic conductivity, while the significance of electrochemical active species in these system has long been ignored...
December 20, 2018: ACS Applied Materials & Interfaces
Ji-Hyun Cha, Eun Bi Park, Sang Wook Han, Young Dok Kim, Duk-Young Jung
Direct synthesis of nanostructured electrode materials on three-dimensional substrates is important for their practical application in electrochemical cells without requiring the use of organic additives or binders. In this study, we present a simple two-step process to synthesize a stable core-shell structured cobalt sulfide/cobalt aluminium hydroxide nanosheet (LDH-S) for pseudocapacitor electrode application. The cobalt aluminium layered double hydroxide (CoAl-LDH) nanoplates were synthesized in basic aqueous solution with a kinetically-controlled thickness...
December 19, 2018: Chemistry, An Asian Journal
Runzhi Zhang, Kang Yan, Anthony Palumbo, Jian Xu, Shichen Fu, Eui-Hyeok Yang
We present an all-solid-state flexible and stretchable pseudocapacitor composed of dodecylbenzenesulfonate-doped polypyrrole (PPy(DBS))-coated vertically aligned carbon nanotubes (VACNTs) partially embedded in a polydimethylsiloxane (PDMS) substrate. VACNTs are grown via atmospheric-pressure chemical vapor deposition (APCVD) on a Si/SiO₂ substrate and transferred onto PDMS. Then the PPy(DBS) film is coated with a surface charge of 300 mC/cm2 on individual carbon nanotubes (CNTs) via electropolymerization...
November 15, 2018: Nanotechnology
Samanta Witomska, Włodzimierz Czepa, Zhaoyang Liu, Alessandro Aliprandi, Dawid Pakulski, Piotr Pawluc, Artur Ciesielski, Paolo Samorì
Towards the introduction of fast faradaic pseudocapacitive behavior and the increase of the specific capacitance of carbon-based electrodes, we have covalently functionalized graphene oxide with a redox active thiourea-formaldehyde polymer yield-ing a multifunctional hybrid system. The multiscale physical and chemical characterization of the novel 3-dimensional hy-brid revealed high material's porosity with high specific surface area (402 m2 g-1) and homogeneous element distribution. The presence of multiple functional groups comprising sulphur, nitrogen and oxygen, provide additional contribution of Faradic redox reaction in supercapacity performance, leading to a high effective electrochemical pseudocapacitance...
December 5, 2018: Journal of the American Chemical Society
Ali Ehsani, Ali Akbar Heidari, Hamid Mohammad Shiri
This review gives an overview of the synthesis, surface and electrochemical investigations over ternary nanocomposite of conductive polymers in the development of new supercapacitors. They utilize both Faradaic and non-Faradaic procedures to store charge, leading to higher specific capacitance and energy density, higher cell voltage, longer life cycle and moderated power density. Owing to a unique combination of features such as superb electrical conductivity, corrosion resistance in aqueous electrolytes, highly modifiable nanostructures, long cycle life and the large theoretical specific-surface area, the use of ternary nanocomposites as a supercapacitor electrode material has become the focus of a significant amount of current scientific researches in the field of energy storage devices...
November 27, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Yinghui Shang, Junjie Wei, Chu Wu, Qigang Wang
Polymer gel electrolytes (PGEs) have been considered as one of the most promising candidates to solve safety and flexibility issues in wearable devices. To supply energy for the daily-used epidermal electronic systems, biaxial stretchability and temperature tolerance are essential for energy storage units. However, the limited choices of PGEs, including fragile poly(vinyl alcohol) and uniaxial stretchable polyacrylamide hydrogel, lag far behind the requirement of wearable supercapacitors. Herein, an adhesive organohydrogel with a water/ethylene glycol binary solvent is tailored as the electrolyte of an all-climate, biaxially stretchable pseudocapacitor...
November 30, 2018: ACS Applied Materials & Interfaces
Pattarachai Srimuk, Juhan Lee, Öznil Budak, Jaehoon Choi, Ming Chen, Guang Feng, Christian Prehal, Volker Presser
Aqueous electrolytes can be used for electrical double-layer capacitors, pseudocapacitors, and intercalation-type batteries. These technologies may employ different electrode materials, most importantly high-surface-area nanoporous carbon, two-dimensional materials, and metal oxides. All of these materials also find more and more applications in electrochemical desalination devices. During the electrochemical operation of such electrode materials, charge storage and ion immobilization are accomplished by non-Faradaic ion electrosorption, Faradaic ion intercalation at specific crystallographic sites, or ion insertion between layers of two-dimensional materials...
October 29, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Tao Ling, Pengfei Da, Xueli Zheng, Binghui Ge, Zhenpeng Hu, Mengying Wu, Xi-Wen Du, Wen-Bin Hu, Mietek Jaroniec, Shi-Zhang Qiao
Atomic-level structure engineering can substantially change the chemical and physical properties of materials. However, the effects of structure engineering on the capacitive properties of electrode materials at the atomic scale are poorly understood. Fast transport of ions and electrons to all active sites of electrode materials remains a grand challenge. Here, we report the radical modification of the pseudocapacitive properties of an oxide material, Zn x Co1- x O, via atomic-level structure engineering, which changes its dominant charge storage mechanism from surface redox reactions to ion intercalation into bulk material...
October 2018: Science Advances
Hui Peng, Rui Zhao, Jing Liang, Sihan Wang, Fei Wang, Jiezi Zhou, Guofu Ma, Ziqiang Lei
Two-dimensional conducting polymers nanosheet prepared by the soft-template-assisted technique in aqueous system still has rarely been reported, especially the formation of nanosheets structure by protonic acid assisted controlling the stability of the micelles method. Herein, a facile, one-step, bottom-up approach is developed to synthesize novel and uniform conductive poly(4-aminodiphenylamine) (P(4-ADPA)) nanosheets with controlled morphology via regulating the proton acid concentration during the self-assembly of surfactant lamellar micelles...
October 31, 2018: ACS Applied Materials & Interfaces
Lushuai Zhang, Trisha L Andrew
Controlling mesoscale organization in thick films of electroactive polymers is crucial for studying and optimizing charge and ion transport in these disordered materials. Conventional approaches focus on directing long-range polymer aggregation and/or crystallization during film formation by using interfaces, flow and/or shear forces. Here, we describe an alternative method that takes advantage of naturally textured biological substrates and vapor-coating to structure thick-conjugated polymer films. Reactive vapor-coating is a technique that enables in situ synthesis of doped conjugated polymers inside a reduced-pressure reactor...
October 26, 2018: ACS Applied Materials & Interfaces
Steffen Heuser, Nianjun Yang, Felix Hof, Anna Schulte, Holger Schönherr, Xin Jiang
High-performance supercapacitors feature big and stable capacitances and high power and energy densities. To fabricate high-performance supercapacitors, 3D 3C-SiC/graphene hybrid nanolaminate films are grown via a microwave plasma-assisted chemical vapor deposition technique. Such films consist of 3D alternating structures of vertically aligned 3C-SiC and graphene layers, leading to high surface areas and excellent conductivity. They are further applied as the capacitor electrodes to construct electrical double layer capacitors (EDLCs) and pseudocapacitors (PCs) in both aqueous and organic solutions...
November 2018: Small
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