Dual‐Encapsulated Highly Conductive and Liquid‐Free Phase Change Composites Enabled by Polyurethane/Graphite Nanoplatelets Hybrid Networks for Efficient Energy Storage and Thermal Management

Abstract

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.

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

“…The faster electrothermal responsibility and shorter charging time at a higher voltage cause the reduction of heat loss, so a higher electrothermal conversion efficiency is produced. 56 As shown in Figure 6f, the temperature variation is consistent with the applied alternating voltage, indicating a flexible and sensitive heating behavior. In Figure 6g, EPU@PW was heated at a constant voltage of 3.4 V for a long-term test.…”

“…Additionally, the electrothermal storage efficiencies at different voltages are calculated and displayed in Figure e and Table S2, which are comparable or superior to those of the previously reported phase change composites (Table S3). The faster electrothermal responsibility and shorter charging time at a higher voltage cause the reduction of heat loss, so a higher electrothermal conversion efficiency is produced . As shown in Figure f, the temperature variation is consistent with the applied alternating voltage, indicating a flexible and sensitive heating behavior.…”

Dopamine-Mediated Bacterial Cellulose/Hexagonal Boron Nitride Composite Films with Enhanced Thermal and Mechanical Performance

“…Heat dissipation has become a growing demand to keep up with the tendency of miniaturization and densification of integrated circuits and electronic devices in the fifth-generation communication era. − The heat accumulation generated in a confined space forms a concentrated hot spot, which closely relates to the service reliability and lifetime of electronic components. − However, the existing thermal management materials, such as electronic packaging materials or equipment components, still suffer from a low thermal conductivity of 1–5 W·m –1 ·K –1 . , In addition, despite the acceptable heat dissipation efficiency of thermal management materials, its poor mechanical properties further limit their practical applications in flexible and collapsible electronic devices. − Therefore, it is of great interest to exploit thermal management materials with high thermal conductivity and excellent mechanical properties. , …”

Recent Developments of Thermal Management Strategies for Lithium‐Ion Batteries: A State‐of‐The‐Art Review

“…To achieve full-temperature thermal management, Luo et al [192] synthesized a series of PA/EG composites that possessed low-electrical resistance of 0.1-0.28 Ω mm. In this regard, the PCM not only kept battery temperature below 55 C through phase-transition enthalpy but also showed preheating function via electrothermal conversion under À20 C. Wu et al [193] also proposed a dualencapsulated PCM for active preheating and passive cooling. The composite PCM had an excellent thermal and electrical conductivity of 27.0 W m À1 K À1 and 51.0 S cm À1 , respectively.…”