Hierarchically Anisotropic Networks to Decouple Mechanical and Ionic Properties for High-Performance Quasi-Solid Thermocells

Abstract

The rapid growth of wearable systems demands sustainable, mechanically adaptable, and eco-friendly energy-harvesting devices. Quasi-solid ionic thermocells have demonstrated the capability of continuously converting low-grade heat into electricity to power wearable electronics. However, a trade-off between ion conductivity and mechanical properties is one of the most challenging obstacles for developing high-performance quasi-solid thermocells. Herein, the trade-off is overcome by designing anisotropic polymer networks to produce aligned channels for ion-conducting and hierarchically assembled crystalline nanofibrils for crack blunting. The ionic conductivity of the anisotropic thermocell has a more than 400% increase, and the power density is comparable to the record of state-of-the-art quasi-solid thermocells. Moreover, compared with the existing quasi-solid thermocells with the optimal mechanical performance, this material realizes biomimetic strain-stiffening and shows more than 1100% and 300% increases in toughness and strength, respectively. We believe this work provides a general method for developing high-performance, cost-effective, and durable thermocells and also expands the applicability of thermocells in wearable systems.

Sorbents for Atmospheric Water Harvesting: From Design Principles to Applications

“…Apart from above extended applications of sorbents, the efficient utilization and management of the thermal energy produced during the sorption/desorption process could also be meaningful for various technologies. Utilizing the lowgrade thermal energy from the sorption-evaporation cycles combined with advanced electronic devices such as photovoltaic panels [97] and thermal cells [98] has great potential for sustainability. For example, Li et al designed a versatile strategy for the cooling of solar panels in which a sorptionbased atmosphere water harvester served as the cooling component (Figure 16a).…”

Thermoelectric energy harvesting for personalized healthcare

“…47 Figure 5C shows assembled thermocell arrays connected with P-type units in series. The TGCs with 27 P-type units achieve a maximum output power of 28 μW and a total voltage of 342 mV at the ΔT of 10 K. 37 When TECs are connected with P-N types in series, 10 P-N units achieve a voltage of 823.3 mV (Figure 6A). 48 In addition, The TGC enables self-healing properties due to physically crosslinked networks, overcoming the limitation of durability for practical applications (Figure 6B).…”

Potential and Challenges of Thermogalvanic Cells for Low-Grade Heat Harvesting

“…Based on the gelatin containing KCl, NaCl, KNO 3 , and Fe(CN) 6 4−/3− , Cheng-Gong et al (2020) gained a prominent thermopower of +17 mV/K through the thermodiffusion of KCl, NaCl, and KNO 3 , as well as the thermogalvanic effect of Fe(CN) 6 4−/3− (Figure 1D). In addition to the studies on the enhancement of thermoelectric performance, the anti-freeze performance (Gao et al, 2021), mechanical properties (Gao et al, 2022), and p-n-type conversion (Duan et al, 2019) are also the focus of research.…”

“…Among the state-of-art options, thermogalvanic cells can generate electricity by the gain and loss of electrons at the two same electrodes under the action of a temperature-dependent redox ionic reaction (Lei et al, 2021;Li et al, 2021). In comparison with the conventional electronic thermoelectrics (Taroni et al, 2018;Chae et al, 2020) and ionic thermos capacitors (Al-zubaidi et al, 2017;Wu et al, 2021), thermogalvanic cells based on redox reactions are not only noise-free and environmentally friendly, but also they enable continuous conversion of lowgrade heat to electricity (Gao et al, 2022). Moreover, the thermogalvanic cells hold the potential to enable an efficient, lightweight, continuous flexible power supply for the burgeoning flexible electronics (e.g., flexible screens and wearable medical electronics) (Liu et al, 2022;Peng et al, 2022;Zhang et al, 2022).…”

“…Moreover, the thermogalvanic cells hold the potential to enable an efficient, lightweight, continuous flexible power supply for the burgeoning flexible electronics (e.g., flexible screens and wearable medical electronics) (Liu et al, 2022;Peng et al, 2022;Zhang et al, 2022). This imposes the challenge of durably optimizing the performance of thermogalvanic cells in terms of thermopower (Duan et al, 2018), mechanical properties (Lei et al, 2021;Gao et al, 2022;Lei et al, 2022), and anti-freezing (Gao et al, 2021), among others. Although the previous researchers presented significant advances, thermogalvanic cells still have challenges in the field of low-grade heat harvesting and flexible power sources.…”