High-performance wood-based thermoelectric sponges for thermal energy harvesting and smart buildings

The development of renewable woods for power generation can help improve the energy efficiency of buildings,and promote the concept design and implementation of“smart buildings”.Here,with specific chemical treatment and hydrothermal synthesis,we demonstrated the practical value of natural wood for thermoelectric power generation in smart buildings.The prepared wood-based thermoelectric sponges show high Seebeck coefficients of 320.5 and 436.6μV/K in the vertical and parallel directions of the longitudinal channel of wood.After 500 cycles of the compressive strain at 20%,the corresponding Seebeck coefficients increase up to 413.4 and 502.1μV/K,respectively,which is attributed to the improved contact and connection between tellurium thermoelectric nanowires.The Seebeck coefficients are much larger than those of most reported inorganic thermoelectric materials.Meanwhile,the thermoelectric sponges maintain excellent thermoelectric and mechanical stability.We further modeled the application value of wood-based thermoelectric sponges in smart buildings for power generation.Relatively high thermoelectric electricity can be obtained,such as in Beijing with over 1.5 million kWh every year,demonstrating the great potential in thermal energy harvest and energy supply.

Highly Stretchable Shape Memory Self-Soldering Conductive Tape with Reversible Adhesion Switched by Temperature

With practical interest in the future applications of next-generation electronic devices,it is imperative to develop new conductive interconnecting materials appropriate for modern electronic devices to replace traditional rigid solder tin and silver paste of high melting temperature or corrosive solvent requirements.Herein,we design highly stretchable shape memory self-soldering conductive(SMSC)tape with reversible adhesion switched by temperature,which is composed of silver particles encapsulated by shape memory polymer.SMSC tape has perfect shape and conductivity memory property and anti-fatigue ability even under the strain of 90%.It also exhibits an initial conductivity of 2772 S cm^(−1) and a maximum tensile strain of~100%.The maximum conductivity could be increased to 5446 S cm^(−1) by decreasing the strain to 17%.Meanwhile,SMSC tape can easily realize a heating induced reversible strong-to-weak adhe-sion transition for self-soldering circuit.The combination of stable conductivity,excellent shape memory performance,and temperature-switching reversible adhesion enables SMSC tape to serve two functions of electrode and solder simultaneously.This provides a new way for conductive interconnecting materials to meet requirements of modern electronic devices in the future.

Highly stretchable double-network gel electrolytes integrated with textile electrodes for wearable thermo-electrochemical cells

Thermo-electrochemical cells(TECs)provide a new potential for self-powered devices by converting heat energy into electricity.However,challenges still remain in the fabrication of flexible and tough gel electrolytes and their compat-ibility with redox actives;otherwise,contact problems exist between electrolytes and electrodes during stretching or twisting.Here,a novel robust and neutral hydrogel with outstanding stretchability was developed via double-network of crosslinked carboxymethyl chitosan and polyacrylamide,which accommodated both n-type(Fe^(2+)/Fe^(3+))and p-type([Fe(CN)_(6)]^(3-)/[Fe(CN)_(6)]^(4-))redox couples and maintained stretchability(>300%)and recoverability(95%compression).Moreover,poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)textile elec-trodes with porous structure are integrated into gel electrolytes that avoid contact issues and effectively boost the P_(max) of n-and p-type thermocell by 76%and 26%,respectively.The optimized thermocell exhibits a quick current density response and is continually fully operational under deformations,which satisfies the working conditions of wearable devices.Multiple thermocells(four pairs)are effectively connected in alternating single n-and p-type cells in series and out-putted nearly 74.3 mV atΔT=10℃.The wearable device is manufactured into a soft-pack thermocells to successfully harvest human body heat and illuminate an LED,demonstrating the potential of the actual application of the thermocell devices.

仿生学中介电聚合物复合材料的研究进展

自然结构、自然现象、动植物形态和人类行为总是给我们提供灵感,激发更多的创造力.可用于制造人工肌肉的介电聚合物复合材料的设计与应用在仿生学领域显示出巨大的潜力.然而,其仍然面临着巨大的挑战,严重阻碍了介电聚合物复合材料的发展.本文系统地综述了近年来自然启发的具有优异性能的单层和多层介电聚合物复合材料的研究进展,并对其结构和特性进行了描述.此外,我们进一步讨论了这种复合材料在集成系统中的应用,包括仿生机器人、医疗保健和生物医学应用.此外,我们还深入分析了这一领域的挑战和前景.模仿自然已经成为介电聚合物复合材料设计和应用的关键.我们相信这种方法将推动智能和医疗行业的持续进步.