Solvated reduced graphene oxide (S-rGO) membranes are stable in organic solvents, and strong acidic, alkaline, or oxidative media. They show high rejections to small molecules with charges the same as that of S-rGO coatings or neutral molecules larger than 3.4 nm, while retaining their high permeances to organic solvents.

Natural vascular plants leaves rely on differences in osmotic pressure, transpiration and guttation to produce tons of clean water, powered by sunlight. Inspired by this, we report a sunlight-driven purifier for high-efficiency water purification and production. This sunlight-driven purifier is characterized by a negative temperature response poly(N-isopropylacrylamide) hydrogel (PN) anchored onto a superhydrophilic melamine foam skeleton, and a layer of PNIPAm modified graphene (PG) filter membrane coated outside. Molecular dynamics simulation and experimental results show that the superhydrophilicity of the relatively rigid melamine skeleton significantly accelerates the swelling/deswelling rate of the PNPG-F purifier. Under one sun, this rational engineered structure offers a collection of 4.2 kg m −2 h −1 and an ionic rejection of > 99% for a single PNPG-F from brine feed via the cooperation of transpiration and guttation. We envision that such a high-efficiency sunlight driven system could have great potential applications in diverse water treatments.

Filtering capacitor is a necessary component in the modern electronic circuit. Traditional filtering capacitor is often limited by its bulky and rigid configuration and narrow workable scope of applications. Here, an aqueous hybrid electrochemical capacitor is developed for alternating current line filtering with an applicable wide frequency range from 1 to 10,000 Hz. This capacitor possesses an areal specific energy density of 438 μF V 2 cm −2 at 120 Hz, which to the best of our knowledge is record high among aqueous electrochemical capacitors reported so far. It can convert arbitrary alternating current waveforms and even noises to straight signals. After integration of capacitor units, a workable voltage up to hundreds of volts (e.g., 200 V) could be achieved without sacrificing its filtering capability. The integrated features of wide frequency range and high workable voltage for this capacitor present promise for multi-scenario and applicable filtering capacitors of practical importance.

Silicon (Si), a promising candidate for next-generation lithium-ion battery anodes, is still hindered by its volume change issue for (de)­lithiation, thus resulting in tremendous capacity fading. Designing carbon-modified Si materials with a void-preserving structure (Si@void@C) can effectively solve this issue. The preparation of Si@void@C, however, usually depended on template-based routes or chemical vapor deposition, which involve toxic reagents, tedious operation processes, and harsh conditions. Here, a facile templateless approach for preparing Si@void@C materials is reported through controlling the growth kinetics of resin, without the use of toxic hydrofluoric acid or harsh conditions. This approach allows great flexibility in tuning the crucial parameters of Si@void@C, such as the carbon shell thickness, the reserved void size, and the number of Si cores coated by a carbon shell. The optimized Si@void@C delivers a large specific capacity (1993.2 mAh g–1 at 0.1 A g–1), excellent rate performance (799.4 mAh g–1 at 10.0 A g–1), and long cycle life (73.5% capacity retention after 1000 cycles at 2.0 A g–1). In addition, a full cell fabricated with a Si@void@C anode and commercial LiFePO4 cathode also displays an impressive cycling performance.

improving electrical conductivity, while relatively less work were aimed to optimize regularly desired microstructure for accelerating mass (Li + ) transfer and enhancing tap density simultaneously (Table S1, Supporting Information). [20][21][22]28,29 ] Actually, as has been recognized that the Li + transport in electrolyte to approach the active site may also be rate-limiting factor at high rates, [ 13,30 ] and the tap density directly infl uence the volumetric energy density of the fi nal LIBs, which is also very important for EVs and HEVs. [ 10,16 ] On the other side, compared with performance study, the theoretical research of this area was relatively rare. [ 1,16 ] Therefore, it is still highly desirable to design an ideal-structured LFP/CNTs composite with substantially improved electronic and ionic transport kinetics as well as high tap density for EVs and HEVs applications, and the inherent reason for electrochemical performance improvment of such kind of composite was also needed to deeply undstood from the theoretical aspect.Herein, we presented a unique hierarchically porous C@LFP/ CNTs microsphere composite via a facile hydrothermal approach combined with high-temperature calcinations using the relative low-cost Fe 3+ source as the raw material. In such a composite, CNTs as an electronic conductive component were in situ and uniformly embedded into the LFP open porous microspheres to form a conductive CNTs network, meanwhile the interlaced pore networks facilitated rapid Li + supplies, which made each C@LFP/CNTs microsphere to be an effective microreactor for fast electrochemical reactions. Meanwhile, the amorphous carbon bridged the CNTs network, and thus further improved the electronic conductivity of the whole composite. Besides, the microsphere morphology guaranteed a large tap density of the composite for high volumetric energy density supplies. It should be noted that CNTs is also an electrochemical capacitor material by storing energy in electric double layer. As reported previously, in a composite electrode, the capacitor component could promote a fast capacity response, which buffered the infl uence on LIB component under high-rate charge or discharge, and thereby, benefi cial for its rate performance and cycling stability. [ 13 ] For comparison purpose, a composite decorated by single amorphous carbon (C@LFP) was also prepared and investigated. The electrochemical test results demonstrated that the C@LFP/ CNTs composite indeed exhibited impressive rate capability (73 mAh g −1 at 60 C) and cycling stability (98% capacity retention over 1000 cycles at 10 C) combined with a high volumetric energy density (443 Wh L −1 at 10 C). To deeper understand the improved electrochemical performance of C@LFP/CNTs, the compound interfacial property of LFP and CNTs were further studied by a density functional theoretical (DFT) calculation.Lithium-ion batteries (LIBs) have been widely investigated in the past two decades for energy storage in electric vehicles (EVs) and hybrid electric vehicles (HEVs) for the...

3D self-supported hierarchical core/shell structured MnCo2O4@CoS nanowire or nanosheet (MCO@CS-NW or NT) arrays were designed for high-performance supercapacitors.

In this work, a unique reduced graphene oxide modified metallic cobalt (rGO/Co) composite, in which Co nanoparticles in situ anchored on rGO sheets, had been synthesized via a facile one pot co-precipitation approach. Such a composite exhibited an impressive performance when used in (asymmetric) supercapacitors. For comparison purposes, pure rGO and Co were also prepared and investigated. Microscopic observation techniques, nitrogen sorption analysis and electrochemical methods et al. were 10 used to characterize the materials' properties. The physical characterizations revealed rGO/Co possessed a "particle on sheet" structure with a "point to face" electronic contact between these two components, and the size of Co was much smaller than pure Co due to the geometric confinement of rGO, as well as a larger Brunauer-Emmett-Teller (BET) surface area resulted from the structure synergistic effect for alleviating the agglomeration of each component. Remarkably, the rGO/Co composite displayed the best 15 electrochemical performances among the three synthesized samples with the capacity as high as 882.7 F·g -1 at a current density of 2 A·g -1 and presented a high rate capability as well. Moreover, a asymmetric supercapacitor using rGO/Co as positive active materiel and activated carbon (AC) as negative active materiel has also been fabricated and tested in the potential window ranged between 0-1.6 V, which had been demonstrated could achieve a maximum energy density of 40.7 Wh·kg -1 at a power density of 20 1585.0 W·kg -1 as well as excellent rate capability and outstanding cycling durability. 65 Among various carbonaceous materials, graphene, a rising star, has attracted many attentions because of its extraordinary electrical stability, large surface area, superior mechanical properties, and good electrochemical stability. [23][24][25][26] Nevertheless, on the one hand, the previous reported research of such kind of 70 composites were in generl in a symmetric capacitor system resulted in a limited improvement in energy density; on the other The prepared rGO/Co//AC asymmetric supercapacitor displayed good electrochemical performances, which achieved a maximum energy density of 40.7 Wh·kg -1 at a power density of 1585.0 W·kg -1 .

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