Suppressing Thermal Negative Effect and Maintaining High-Temperature Steady Electrical Performance of Triboelectric Nanogenerators by Employing Phase Change Material

A Trimode Thermoregulatory Flexible Fibrous Membrane Designed with Hierarchical Core-Sheath Fiber Structure for Wearable Personal Thermal Management

Advanced textiles designed for personal thermal management contribute to thermoregulation in an individual and energy-saving manner. Textiles incorporated with phase changing materials (PCMs) are capable of bridging the supply and demand for energy by absorbing and releasing latent heat. The integration of solar heating and the Joule heating function supplies multidriving resources, facilitates energy charging and storage, and expands the service time and application scenarios. Herein, we report a fibrous membrane-based textile that was developed by designing the hierarchical core-sheath fiber structure for trimode thermal management. Especially, coaxial electrospinning allows an effective encapsulation of PCMs, with high heat enthalpy density (106.9 J/g), enabling the membrane to buffer drastic temperature changes in the clothing microclimate. The favorable photothermal conversion performance renders the membrane with the high saturated temperature of 70.5 °C (1 sun), benefiting from the synergistic effect of multiple light harvesters. Moreover, a conductive coating endows the composite membrane with an admirable electrothermal conversion performance, reaching a saturated temperature of 73.8 °C (4.2 V). The flexible fibrous membranes with the integrated performance of reversible phase change, multi-source-driven heating, and energy storage present great advantages for all-day, energy-saving, and wearable individual thermal management applications.

Fluidic phase-change materials with continuous latent heat from theoretically tunable ternary metals for efficient thermal management

Phase-change materials (PCMs), as important energy storage materials (ESMs), have been widely used in heat dissipation for electronics. However, PCMs are encountering huge challenges since the extremely limited space in microelectronics largely suppresses the applied volume of PCMs, which demands excellent PCMs that can fully utilize the valuable latent heat. This work successfully found a universal strategy toward powerful ESMs from fluidic ternary metals (TMs, GaInSn as a representative TM in this work). TMs exhibit high thermal conductivity (20.3 W m-1 K-1) and significantly effective latent heat (115 J/cm3) and, more important, show continuous phase transition and full utilization of the valuable latent heat. Interestingly, theoretical prediction through ternary phase diagram is carried out to easily tune the melting range, latent heat, and fluidity (viscosity) of TMs to adapt with different service conditions. As a result, thermally conductive silicone grease can be conveniently fabricated via simple shear mixing of TM and polymers. Such thermally conductive TM grease inherits the merits of TM, exhibiting continuous thermal control over daily electronics according to thermal shock performance.