Efficient thermal energy harvesting using phase‐change materials (PCMs) has great potential for cost‐effective thermal management and energy storage applications. However, the low thermal conductivity of PCMs (KPCM) is a long‐standing bottleneck for high‐power‐density energy harvesting. Although PCM‐based nanocomposites with an enhanced thermal conductivity can address this issue, achieving a higher K (>10 W m−1 K−1) at filler loadings below 50 wt% remains challenging. A strategy for synthesizing highly thermally conductive phase‐change composites (PCCs) by compression‐induced construction of large aligned graphite sheets inside PCCs is demonstrated. The millimeter‐sized graphite sheet consists of lateral van‐der‐Waals‐bonded and oriented graphite nanoplatelets at the micro/nanoscale, which together with a thin PCM layer between the sheets synergistically enhance KPCM in the range of 4.4–35.0 W m−1 K−1 at graphite loadings below 40.0 wt%. The resulting PCCs also demonstrate homogeneity, no leakage, and superior phase change behavior, which can be easily engineered into devices for efficient thermal energy harvesting by coordinating the sheet orientation with the thermal transport direction. This method offers a promising route to high‐power‐density and low‐cost applications of PCMs in large‐scale thermal energy storage, thermal management of electronics, etc.

Fresh water scarcity is a globally significant challenge threatening the development of human society. Sorption-based atmospheric water harvesting offers an appealing way to solve this challenge by extracting clean water...

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Phase change materials (PCMs) have been widely used for passive thermal management and energy storage due to the high latent heat capacity near phase transition points. However, the low thermal...

Phase change materials (PCMs) are regarded as promising candidates for realizing zero‐energy thermal management of electronic devices owing to their high thermal storage capacity and stable working temperature. However, PCM‐based thermal management always suffers from the long‐standing challenges of low thermal conductivity and liquid leakage of PCMs. Herein, a dual‐encapsulation strategy to fabricate highly conductive and liquid‐free phase change composites (PCCs) for thermal management by constructing a polyurethane/graphite nanoplatelets hybrid networks is reported. The PCM of polyethylene glycol (PEG) is first infiltrated into the cross‐linked network of polyurethane (PU) to synthesize hybridized semi‐interpenetrated composites (PEG@PU), and then incorporated with reticulated graphite nanoplatelets (RGNPs) via pressure‐induced assembly to fabricate highly conductive PCCs (PEG@PU‐RGNPs). The hybrid networks enable the PCCs to show excellent mechanical strength, liquid‐free phase change, and stable thermal property. Notably, the dual‐encapsulated PCCs exhibit high thermal and electrical conductivities up to 27.0 W m−1 K−1 and 51.0 S cm−1, superior to the state‐of‐the‐art PEG‐based PCCs. Furthermore, the PCC‐based energy device is demonstrated for efficient battery thermal management toward versatile demands of active preheating at a cold environment and passive cooling at a hot ambient. Overall, this work provides a promising route for fabricating highly conductive and liquid‐free PCCs toward thermal management.

Effective battery thermal management (BTM) is critical to ensure fast charging/discharging, safe, and efficient operation of batteries by regulating their working temperatures within an optimal range. However, the existing BTM methods not only are limited by a large space, weight, and energy consumption but also hardly overcome the contradiction of battery cooling at high temperatures and battery heating at low temperatures. Here we propose a near-zero-energy smart battery thermal management (SBTM) strategy for both passive heating and cooling based on sorption energy harvesting from air. The sorption-induced reversible thermal effects due to metal–organic framework water vapor desorption/sorption automatically enable battery cooling and heating depending on the local battery temperature. We demonstrate that a self-adaptive SBTM device with MIL-101(Cr)@carbon foam can control the battery temperature below 45 °C, even at high charge/discharge rates in hot environments, and realize self-preheating to ∼15 °C in cold environments, with an increase in the battery capacity of 9.2%. Our approach offers a promising route to achieving compact, liquid-free, high-energy/power-density, low-energy consumption, and self-adaptive smart thermal management for thermo-related devices.

Water and electricity scarcity are two global challenges, especially in arid and remote areas. Harnessing ubiquitous moisture and sunlight for water and power generation is a sustainable route to address these challenges. Herein, we report a moisture-induced energy harvesting strategy to realize efficient sorption-based atmospheric water harvesting (SAWH) and 24-hour thermoelectric power generation (TEPG) by synergistically utilizing moisture-induced sorption/desorption heats of SAWH, solar energy in the daytime and radiative cooling in the nighttime. Notably, the synergistic effects significantly improve all-day thermoelectric power density (~346%) and accelerate atmospheric water harvesting compared with conventional designs. We further demonstrate moisture-induced energy harvesting for a hybrid SAWH-TEPG device, exhibiting high water production of 750 g m−2, together with impressive thermoelectric power density up to 685 mW m−2 in the daytime and 21 mW m−2 in the nighttime. Our work provides a promising approach to realizing sustainable water production and power generation at anytime and anywhere.