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Hybrid electric storage systems that combine capacitive and faradaic materials need to be well designed to benefit from the advantages of batteries and supercapacitors. The ultimate capacitive material is graphite (GR), yet high capacitance is usually not achieved due to restacking of its sheets. Therefore, an appealing approach to achieve high power and energy systems is to embed a faradaic 2D material in between the graphite sheets. Here, a simple one‐step approach was developed, whereby a faradaic material [layered double hydroxide (LDH)] was electrochemically formed inside electrochemically exfoliated graphite. Specifically, GR was exfoliated under negative potentials by CoII and, in the presence of MnII, formed GR‐CoMn‐LDH, which exhibited a high areal capacitance and energy density. The high areal capacitance was attributed to the exfoliation of the graphite at very negative potentials to form a 3D foam‐like structure driven by hydrogen evolution as well as the deposition of CoMn‐LDH due to hydroxide ion generation inside the GR sheets. The ratio between the CoII and MnII in the CoMn‐LDH was optimized and analyzed, and the electrochemical performance was studied. Analysis of a cross‐section of the GR‐CoMn‐LDH confirmed the deposition of LDH inside the GR layers. The areal capacitance of the electrode was 186 mF cm−2 at a scan rate of 2 mV s−1. Finally, an asymmetric supercapacitor was assembled with GR‐CoMn‐LDH and exfoliated graphite as the positive and negative electrodes, respectively, yielding an energy density of 96.1 μWh cm−3 and a power density of 5 mW cm−3. [ABSTRACT FROM AUTHOR]

The synthesis of multi‐carbon products through electrochemical CO2 reduction reactions has attracted great interest from researchers. Herein, nitrogen‐ and carbon‐doped copper nanocatalyst (NC−Cu) containing abundant Cu−N−C active sites was prepared by thermal decomposition of the complexes containing copper and melamine. The NC−Cu catalyst exhibited an ideal current density of 22 mA cm−2 at −0.93 V versus reversible hydrogen electrode (vs. RHE) in CO2‐saturated 0.5 M KHCO3 medium, with ethanol as the predominant product at −0.93 V (vs. RHE) and a maximum Faraday efficiency of 31 %. The current density of the catalyst remained almost unchanged after 20 h of electrolysis, indicating its excellent stability. The excellent catalytic ability is attributed to the abundant Cu−N−C active sites of NC−Cu with 3D porous microstructure. [ABSTRACT FROM AUTHOR]

Cobalt‐glycolate (Co‐glycolate) is a kind of layered coordination polymer with abundant electrochemically active sites but low conductivity. The fabrication of heterostructures is a novel strategy to enhance the electrical conductivity. Herein, Co‐glycolate serves as a host substrate for the in situ growth of guest ZIF‐67 to build MOFs‐on‐CPs heterostructures (named Co‐glycolate /ZIF‐67) via a simple ligand‐exchange method as an anode for lithium‐ion batteries. A heterojunction interface with distorted lattice between the Co‐glycolate phase and the ZIF‐67 phase can be observed. Theoretical calculations and experimental results simultaneously prove that the formed heterojunction reduces the band gap and enhances the conductivity. Compared with both single components, optimized Co‐glycolate/ZIF‐67 shows a higher capacity and better cycling and rate performances due to the improved charge‐transfer rate of the heterostructure. Its specific capacity remains at 652 mAh g−1 after 800 cycles at 1 A g−1. These excellent electrochemical properties can be due to the smaller size, rough surface, and strong combination of a unique heterostructure as well as to the greatly reduced band gap of the individual components. A lithium‐storage mechanism for Co‐glycolate/ZIF‐67 was proposed. This work provides a new strategy for building MOFs‐on‐CPs heterostructures to improve the electrochemical performance of metal‐glycolate‐based electrode materials for energy‐storage and conversion systems. [ABSTRACT FROM AUTHOR]

Wearable electronic devices are the new darling of consumer electronics, and energy storage devices are an important part of them. Here, a wearable lithium‐sulfur (Li‐S) bracelet battery using three‐dimensional (3D) printing technology (additive manufacturing) is designed and manufactured for the first time. The bracelet battery can be easily worn to power the wearable device. The "additive" manufacturing characteristic of 3D printing provides excellent controllability of the electrode thickness with much simplified process in a cost‐effective manner. Due to the conductive 3D skeleton providing interpenetrating transmission paths and channels for electrons and ions, the 3D Li‐S battery can provide 505.4 mAh g−1 specific capacity after 500 cycles with an active material loading as high as 10.2 mg cm−1. The practicality is illustrated by wearing the bracelet battery on the wrist and illuminating the red light‐emitting diode. Therefore, the bracelet battery manufactured by 3D printing technology can address the needs of the wearable power supply. [ABSTRACT FROM AUTHOR]

Supercapacitors are developing in terms of high power and energy densities. Carbon materials can meet this challenge to a certain extent. A sustainable high‐performance carbon material for supercapacitors was prepared through the simple and green thermal pyrolysis of orange peels as raw materials by using KOH as an activator. The biomass‐derived carbon materials activated at different temperatures were evaluated as electrode materials. The adsorption properties, structure, and surface elemental chemical states of the prepared materials were studied. Carbonation temperature plays a key role in the preparation of materials, and it has different effects on the physical and electrochemical properties of materials. The opc700 and opc800 samples have large pore volumes, which provide the necessary space for the storage of electrolyte ions. The temperature has a pronounced effect on the specific surface area and the electrochemical performance. The specific surface area of opc800 is as high as 2004 m2 g−1 and the pore volume is 1.24 cm3 g−1. The maximum specific capacity of opc800 is 306.6 F g−1 at 0.5 A g−1 and the specific capacitance is 251.2 F g−1 at 20 A g−1. [ABSTRACT FROM AUTHOR]

Abstract: Pyrrole was utilized to induce the cross‐link of graphene oxide, resulting in a stable hydrogel. Following, polypyrrole/graphene composite was prepared using direct microwave treatment of this pyrrole‐induced hydrogel. Where, graphene oxide was chemically reduced and pyrrole in the composite was polymerized. The polypyrrole was homogeneously distributed throughout the graphene sheets. The as‐synthesized composite had a three‐dimensional, cross‐linked structure with advanced electro‐catalytic properties for hydroquinone and catechol. This feature was demonstrated by the superior electrochemical reversibility and good peak separation exhibited by the novel composite material. Accordingly, the detection of the two dihydroxybenzenes using this material produced a detection limit of 0.88 μM for hydroquinone and 0.69 μM for the catechol. [ABSTRACT FROM AUTHOR]

Abstract: A new efficient composite catalyst (CuIMnFeIIIO/NG) for oxygen reduction reaction (ORR) in both alkaline and neutral media, is successfully prepared via a facile, clean, low‐cost and reproducible solvothermal method without any further treatments. The nanoparticles consisting of crystalline phases of Fe2O3, MnCO3 and amorphous Cu2O&MnxOy (CuIMnO), are anchored on nitrogen‐doping graphene (N/C atomic ratio up to 10.56 %), which offer various active sites toward ORR. The synergistic catalytic effect between these components affords excellent ORR performance with comparable onset potential and current density to commercial Pt/C in both pH‐situations, and a 4‐electron‐transfer path during oxygen reduction. Furthermore, comparative experiment results are discussed to describe the different degrees of ORR contribution in different medium from metal species and nitrogen doping. Meanwhile, superior methanol tolerance and high stability of CuIMnFeIIIO/NG can make it a promising alternative for expensive commercial Pt‐based electrocatalysts in corresponding alkaline and neutral fuel cells. [ABSTRACT FROM AUTHOR]

Abstract: The large‐scale, low‐cost preparation of Pt‐based catalysts with high activity and durability for the methanol oxidation reaction is still challenging. The key to achieving this aim is finding suitable supporting materials. In this paper, N‐doped carbon nanofibrous networks are prepared by annealing a gel containing two inexpensive and ecofriendly precursors, that is, bacterial cellulose and urea, for the loading of Pt nanoparticles. An undoped analogue is also prepared for comparison. Meanwhile, the effect of the annealing temperature on the performance of the catalysts is evaluated. The results show that the N doping and higher annealing temperature can improve the electron conductivity of the catalyst and provide more active sites for the loading of ultrafine Pt nanoparticles with a narrow size distribution. The best catalyst exhibits a remarkably high electrocatalytic activity (627 mA mg−1), excellent poison tolerance, and high durability. This work demonstrates an ideal Pt supporting material for the methanol oxidation reaction. [ABSTRACT FROM AUTHOR]

Constructing heterogeneous components with a yolk−shell structure is highly desirable for improving the lithium-storage performance of metal oxides, owing to the unique synergies of nanostructures and composite materials. In this work, a novel heterogeneous hybrid of yolk−shell CuO@CuFe2O4 was synthesized through a simple two-step method. Starting with Cu2O, the yolk−shell precursor was prepared through an interfacial reaction. After subsequent heat treatment of the precursor in air, yolk−shell CuO@CuFe2O4 was obtained. A reasonable mechanism for the formation process of the yolk−shell CuO@CuFe2O4 has been presented. The relatively high electrical conductivity of CuFe2O4, unique yolk−shell structure, and firm shell of the CuO@CuFe2O4 account for the extremely enhanced electrochemical properties compared to bare CuO. In particular, discharge capacities of 505 and 36 mA h g−1 were delivered after 200 cycles at 500 mA g−1 by the yolk−shell CuO@CuFe2O4 and bare CuO, respectively. This work not only provides a promising alternative anode material for lithium-ion batteries, but also develops a new strategy to design the nanostructure and components of metal oxides for application in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Heterostructured composites, inheriting the integrated properties of the individual components due to the synergistic effect, have engendered great attention in materials science and energy storage. However, conventional biphasic heterostructures not only optimize the performance of the composites but also aggregate the inevitable drawbacks, which can be addressed with the construction of the triphasic heterostructures by introducing an appropriate intermediate phase, significantly. Herein, a two‐dimensional (2D) double‐heterostructures MoSe2‐TiO2‐MXene anode is architected for Li‐ion storage, which combines the advantages of the high theoretical capacity of MoSe2 and metallic conductivity of MXene. Besides, the in‐situ derived TiO2 can alleviate the irreversible phase transition of MoSe2, arising from the low electronic/ionic conductivities, through electronic coupling effects. Meanwhile, the intermediate phase of TiO2 can further prevent the restacking issue of MXene, thus sustaining its high conductivity. Finally, the three‐dimensional (3D) printing technology is employed to further improve the kinetics of the electrodes for Li‐ion capacitors (LICs), which deliver the power density of 5563 W kg−1 at an energy density of 51 Wh kg−1, and a remarkable cycling stability for 20 000 cycles at 1 A g−1. This work deepens the understanding of the influence of heterostructured engineering on the design of high‐energy/power storage devices. [ABSTRACT FROM AUTHOR]

The title coordination complex, [Ni(C14H14O2PS2)2(C12H8N2)] or [Ni( pMePh-dtp)2(phen)] (phen is 1,10-phenanthroline; dtp is di­aryl­di­thio­phosphate), has a non-crystallographic twofold axis of symmetry through the Ni atom and the phen moiety. Two O, O-di- p-tolyl­di­thio­phosphate (dtp) ions act as bidentate ligands. The central metal atom is coordinated by four S atoms from two dtp groups and two N atoms from the phen ligand. The title compound displays distorted octahedral geometry around the central Ni atom. [ABSTRACT FROM AUTHOR]

In the title compound, [Ni(C6H14O2PS2)2(C5H6N2)2], the coordination around the Ni atom, which lies on a crystallographic centre of symmetry, is octahedral with the S atoms from the di­thio­phosphate ligands occupying the equatorial positions, while the axial positions are occupied by the ring N atoms of the 2-amino­pyridine ligands. The mol­ecules form layers in the bc plane which are stacked in the direction of the a axis. [ABSTRACT FROM AUTHOR]

In the title complex, [Ni(Im)6]( iPr-dtp)2 or [Ni(C3H4N2)6](C6H14O2PS2)2, the coordination around the Ni atom, located on an inversion centre, is octhahedral with all positions being occupied by tertiary N atoms of the imidazole moieties. Hydro­gen bonds link the anions and cations into a two-dimensional network in the bc plane. [ABSTRACT FROM AUTHOR]

In the structure of the title compound, [CuII­(en)2][(EtO)2P(S)S]2 (en is ethyl­ene­di­amine) or [Cu(C2H8N2)2](C4H10O2PS2)2, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethyl­enedi­amine mol­ecules. The diethyl di­thio­phosphate moieties, (EtO)2P(S)S−, act as counter-anions. [ABSTRACT FROM AUTHOR]

In the structure of the title compound, [Cu(II)(en)(2)][(EtO)(2)P(S)S](2) (en is ethylenediamine) or [Cu(C(2)H(8)N(2))(2)](C(4)H(10)O(2)PS(2))(2), the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethylenediamine molecules. The diethyl dithiophosphate moieties, (EtO)(2)P(S)S(-), act as counter-anions.