The heating and cooling energy consumption of buildings accounts for about 15% of national total energy consumption in the United States. In response to this challenge, many promising technologies with minimum carbon footprint have been proposed. However, most of the approaches are static and monofunctional, which can only reduce building energy consumption in certain conditions and climate zones. Here, we demonstrate a dual-mode device with electrostatically-controlled thermal contact conductance, which can achieve up to 71.6 W/m2 of cooling power density and up to 643.4 W/m2 of heating power density (over 93% of solar energy utilized) because of the suppression of thermal contact resistance and the engineering of surface morphology and optical property. Building energy simulation shows our dual-mode device, if widely deployed in the United States, can save 19.2% heating and cooling energy, which is 1.7 times higher than cooling-only and 2.2 times higher than heating-only approaches.

abundance, as well as almost unlimited sodium resources on earth, sodium-ion batteries (SIBs or NIBs) are continuously attracting increasing attentions in both of the academic and industrial fields as competitive alternatives for the possible replacement of LIBs. [2][3][4] Similar with the performance limit issues in LIB systems, the key challenges for the application and commercialization of NIBs are regarded as the appropriate electrode material selection and design. [5][6][7] Among the various candidates for NIB anodes, titanium dioxide (TiO 2 ) is a promising choice on account of its several superiorities such as structural stability based on intercalation mechanism, safety insurance due to the high working voltage, environmental friendly, and low cost. [8][9][10][11][12][13] However, the relatively low specific capacity and inferior rate capability of TiO 2 -based anode materials make them still have the necessity of promotion and optimization. To relieve these natural drawbacks, hollow, hierarchical, and porous architectures are proved to be effective for meliorating the sluggish Na + diffusion kinetics, increasing the Insertion-type anode materials with beneficial micro-and nanostructures are proved to be promising for high-performance electrochemical metal ion storage. In this work, heterostructured TiO 2 shperes with tunable interiors and shells are controllably fabricated through newly proposed programs, resulting in enhanced pseudocapacitive response as well as favorable Na + storage kinetics and performances. In addition, reasonably designed nanosheets in the extrinsic shells are also able to reduce the excess space generated by hierarchical structure, thus improving the packing density of TiO 2 shperes. Lastly, detailed density functional theory calculations with regard to sodium intercalation and diffusion in TiO 2 crystal units are also employed, further proving the significance of the surface-controlled pseudocapacitive Na + storage mechanism. The structure design strategies and experimental results demonstrated in this work are meaningful for electrode material preparation with high rate performance and volume energy density.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Graphite has dominated the market of anode materials for lithium-ion batteries in applications such as consumer electronic devices and electric vehicles. As commercial graphite anodes are approaching their theoretical capacity, significant efforts have been dedicated towards higher capacity by blending capacity-enhancing additives (e.g., Si) with graphite particles. In spite of the improved gravimetric capacity, the areal capacity of such composite anodes might decrease due to excess void spaces and an incompatible material size distribution. Herein, a rational design of compact graphite/Si/SiO2 ternary composites has been proposed to address the abovementioned issues. Si/SiO2 clusters with an optimal particle size are homogeneously dispersed in the interstitial spaces between graphite particles to promote the packing density, leading to a higher areal capacity than that of pure graphite with equivalent mass loading or electrode thickness. By taking the full intrinsic advantages of graphite, Si, and SiO2, the composite electrodes exhibit 553.6 mAh g–1 after 700 cycles with a capacity retention of 95.2%. Furthermore, the graphite/Si/SiO2 electrodes demonstrate a high coulombic efficiency with an average of 99.68% from 2nd to 200th cycles and areal capacities above 1.75 mAh cm–2 during 200 cycles with an areal mass loading as high as 4.04 mg cm–2. A packing model has been proposed and verified by experimental investigation as a design principle of densely compacted anodes. The effective strategy of introducing Si/SiO2 clusters into the void spaces between graphite particles provides an alternative solution for implementation of graphite–Si composite anodes in next-generation Li-ion cells.

Thermal management is ubiquitous in the modern world and indispensable for a sustainable future. Radiative heat management provides unique advantages because the heat transfer can be controlled by the surface. However, different object emissivities require different tuning strategies, which poses challenges to develop dynamic and universal radiative heat management devices. Here, we demonstrate a triple-mode midinfrared modulator that can switch between passive heating and cooling suitable for all types of object surface emissivities. The device comprises a surface-textured infrared-semiabsorbing elastomer coated with a metallic back reflector, which is biaxially strained to sequentially achieve three fundamental modes: emission, reflection, and transmission. By analyzing and optimizing the coupling between optical and mechanical properties, we achieve a performance as follows: emittance contrast Δε = 0.58, transmittance contrast Δτ = 0.49, and reflectance contrast Δρ = 0.39. The device can provide a new design paradigm of radiation heat regulation for wearable, robotics, and camouflage technologies.

Podocytes derived from human induced pluripotent stem (hiPS) cells are enabling studies of kidney development and disease. However, many of these studies are carried out in traditional tissue culture plates that do not accurately recapitulate the molecular and mechanical features necessary for modeling tissue- and organ-level functionalities. Overcoming these limitations requires the design and application of tunable biomaterial scaffolds. Silk fibroin is an attractive biomaterial due to its biocompatibility and versatility, which include its ability to form hydrogels, sponge-like scaffolds, and electrospun fibers and membranes appropriate for tissue engineering and biomedical applications. In this study, we show that hiPS cells can be differentiated into post-mitotic kidney glomerular podocytes on electrospun silk fibroin membranes functionalized with laminin. The resulting podocytes remain viable and express high levels of podocyte-specific markers consistent with the mature cellular phenotype. The resulting podocytes were propagated for at least two weeks, enabling secondary cell-based applications and analyses. This study demonstrates for the first time that electrospun silk fibroin membrane can serve as a supportive biocompatible platform for human podocyte differentiation and propagation. We anticipate that the results of this study will pave the way for the use of electrospun membranes and other biomimetic scaffolds for kidney tissue engineering, including the development of co-culture systems and organs-on-chips microphysiological devices.