Solar steam generation, a sustainable water‐purification technology, holds substantial promise in resolving the global issue of shortage of drinkable water. Here, the design, fabrication, and high‐performance of an innovative 3D solar steamer, offering synergistic high‐efficiency steaming and heavy metal removal functions are reported. The device is made of synthesized carbon‐molybdenum‐disulfide microbeads electrostatically assembled on a 3D polyurethane sponge. The mesoporous composite sponge also serves as a freestanding water reservoir that avoids one‐side contact to bulk water, effectively suppressing the commonly observed parasitic heat loss, and offering a high energy efficiency of 88%. When being sculpted into a 3D spoke‐like structure, the composite sponge achieves one of the highest evaporation rates of 1.95 kg m−2 h−1 at 1 sun. The solar steamer is demonstrated for water treatment, i.e., decontamination of metal ions, disinfection, and reducing alkalinity and hardness of river water. Particularly, the strong mercury adsorption of MoS2 reduces mercury levels from 200 to 1 ppb, meeting the stringent standard set by the Environmental Protection Agency, which is the first demonstration of mercury‐removal powered by solar energy. The unique design, fabrication, water‐handling strategy, and mercury‐removal function of this high‐performance solar steamer can inspire new paradigms of water treatment technologies.

Flexible energy storage devices play a pivotal role in realizing the full potential of flexible electronics. This work presents high-performance, allsolid-state, flexible supercapacitors by employing an innovative multilevel porous graphite foam (MPG). MPGs exhibit superior properties, such as large specific surface area, high electric conductivity, low mass density, high loading efficiency of pseudocapacitive materials, and controlled corrugations for accommodating mechanical strains. When loaded with pseudocapacitive manganese oxide (Mn 3 O 4 ), the MPG/Mn 3 O 4 (MPGM) composites achieve a specific capacitance of 538 F g −1 (1 mV s −1 ) and 260 F g −1 (1 mV s −1 ) based on the mass of pure Mn 3 O 4 and entire electrode composite, respectively. Both are among the best of Mn 3 O 4 -based supercapacitors. The MPGM is mechanically robust and can go through 1000 mechanical bending cycles with only 1.5% change in electric resistance. When integrated as all-solid-state symmetric supercapacitors, they offer a full cell specific capacitance as high as 53 F g −1 based on the entire electrode and retain 80% of capacitance after 1000 continuous mechanical bending cycles. Furthermore, the all-solid-state flexible supercapacitors are incorporated with strain sensors into self-powered flexible devices for detection of both coarse and fine motions on human skins, i.e., those from finger bending and heart beating.

The practical applications of wearable electronics rely on the successful development of flexible and integrable energy devices with small footprints. This work reports a completely new type of graphite foams made of strategically created superstructures with covalentlyattached diverging microtubes, and their applications as electrode supports for binder-free and additive-free flexible supercapacitors. Owing to the enhanced volumetric surface areas compared to conventional graphite foams, a high loading of pseudocapacitive materials (Mn 3 O 4 , 3.91 mg cm -2 , 78 wt%) has been achieved. The supercapacitors provide areal capacitances as high as 820 mF cm -2 at 1 mV s -1 , while still maintaining high rate capability and 88% retention of capacitance after 3 000 continuous charging and discharging cycles.When assembled as all-solid-state flexible symmetric supercapacitors, they offer one of the This article is protected by copyright. All rights reserved. 2 highest full-cell capacitance (191 mF cm -2 ) among similar manganese oxide/graphene foams, and retain 80% capacitance after 1000 mechanical cycles. The potential of such flexible supercapacitors is also manifested by directly powering electric nanomotors that can trace along letters "U" and T", which is the first demonstration of flexible supercapacitors for wireless/portable nanomanipulation systems. This work could inspire a new paradigm in designing and creating 3D porous micro/nanosuperstructures for an array of self-powered electronic and nanomechanical applications.

We find that the initial, solvent-cast state of nanoparticles (NPs) in a polymer matrix temporally evolves during thermal annealing such that, at steady state, NPs maximize their distance from each other subject to mass balance constraints. The observed timescales for this unexpected structural reorganization, as probed by small-angle X-ray scattering, are temperature-dependent and can be prohibitively large, especially at temperatures around and below 1.2T g. X-ray photon correlation spectroscopy measurements during reorganization reveal that the collective NP dynamics slow down with annealing at constant temperature; this is accompanied by changes in the low-frequency regime in macroscopic viscoelastic measurements in equilibrated materials. By ruling out other potential sources for these effects (i.e., electrostatic interactions, adsorbed layers), we attribute these results to a long-ranged repulsive force between the NPs caused by fluctuations in the polymer phase, i.e., the “anti-Casimir” effect proposed by Obhukhov and Semenov [Long-range interactions in polymer melts: The anti-Casimir effect038305Phys Rev Lett200595 Thus, our results highlight the important role of long-term, slow NP reorganization on the structure and, subsequently, the properties of polymer nanocomposites (PNCs), even in the case of nominally miscible polymer nanoparticle hybrids.

It is now commonly accepted that poly(ethylene oxide) (PEO) displays favorable charge transport relative to most polymers. To understand the origins of this singular behavior, we employ coarse-grained representations that allow us to not only model lithium hexafluorophosphate (LiPF 6 ) transport in PEO but also systematically vary the polarity of the polymer, μ, and the distance of approach of Li + to the monomer, σ Li − PEO . Such variations are not easily achieved in the framework of atomistically detailed models. Specifically, PEO is modeled as a Kremer−Grest bead-spring polymer at the Kuhn scale with Stockmayer dipoles embedded in each bead. This model captures both the local electrostatic interactions between Li + and the polymer chain (r ≈ 2 − 5 Å) and the structural features on the polymer chain length scale (⟨R 2 ⟩/M w ≈ 0.7 Å 2 •mol g −1 ). We focus on one composition, EO:Li = 15.4:1, and find that the ionic conductivity of the electrolyte is maximized at intermediate μ and σ Li − PEO due to the sensitive interplay of electrolyte coordination structure (i.e., salt dissolution into the PEO vs. phase separation of salt from the polymer) and the short-and long-time dynamics of all three electrolyte components (chain monomers and the two salt ions). At 353 K, this coarse-grained model predicts the ionic conductivity (∼10 −3 S cm −1 ) and ion self-diffusivities (∼10 −7 cm 2 s −1 ) to within an order of magnitude of experimental results and previous atomistic simulations on PEO. These results indicate that the structure and dynamics of fully atomistic electrolyte models are well-approximated in this coarse-grained model. Looking ahead, this representation should thus be useful to test the effect of surfaces and nanoconfinement on such systems where ionic interactions dominate.