Thermal interface materials with high thermal conductivity are the best choice to solve the current overheating problem of electronic devices, and the choice of thermal conductive filler is a key factor affecting the performance of thermal interface composites. Hexagonal boron nitride sheet is considered to be ideal thermal conductive filler, but the thermal conductive effect of single filler is still insufficient to meet actual needs. Here, a new type of hybrid filler mixed with boron nitride sheet and boron phosphide particles is used to prepare epoxy based composites. When the filler volume fraction is 40%, the thermal conductivity of composites reaches 3.18 W m −1 K −1 . Under the same content, the thermal conductivity of the composites with mixed fillers outperforms those with boron nitride sheet alone. At the same time, the composite material shows high breakdown strength of 46 kV mm −1 . This work provides a new way to prepare thermal interface materials with high thermal conductivity for modern electronic packaging. Graphical Abstract
Juan Zhang,Yanen Wang,Qinghua Wei,Mingyang Li,Xiaohu Chen,Jiayi Zhou
Conductive self-healing hydrogels, as an emerging flexible material, have been extensively studied in flexible sensors which have great application potential in the field of wearable electronic devices. However, hydrogels are prone to freezing at low temperatures, resulting in reduced or even lost flexibility, conductivity and self-healing properties. Besides, manufacturing method, processing time and cost of hydrogel-based sensors remain extremely challenging, hindering their application in complex and extreme environments. The hydrogel with excellent strain-sensing properties and outstanding anti-freezing properties was fabricated by 3D printing technology and solvent displacement method. The VP-SPB-EG hydrogel has excellent anti-freezing performance (−80 °C). In particular, this hydrogel exhibits excellent self-healing performance (120 s) at −80 °C. In addition, VP-SPB-EG hydrogel-based has high stretchability (1850 %) and sensitivity (GF: 27.82) can be used to detect strain changes caused by human joint movements. Therefore, this flexible hydrogel-based sensor has broad application prospects for wearable devices in extreme environments.
Electrocatalysis has emerged as an attractive way for artificial CO 2 fixation to CH 3 OH, but the design and development of metal-free electrocatalyst for highly selective CH 3 OH formation still remains a key challenge. Here, it is demonstrated that boron phosphide nanoparticles perform highly efficiently as a nonmetal electrocatalyst toward electrochemical reduction of CO 2 to CH 3 OH with high selectivity. In 0.1 m KHCO 3 , this catalyst achieves a high Faradaic efficiency of 92.0% for CH 3 OH at −0.5 V versus reversible hydrogen electrode. Density functional theory calculations reveal that B and P synergistically promote the binding and activation of CO 2 , and the rate-determining step for the CO 2 reduction reaction is dominated by *CO + *OH to *CO + *H 2 O process with free energy change of 1.36 eV. In addition, CO and CH 2 O products are difficultly generated on BP (111) surface, which is responsible for the high activity and selectivity of the CO 2 -to-CH 3 OH conversion process.
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