No abstract

Bi2Te3-based compounds are currently the most commercially relevant thermoelectric materials near room temperature. They are prepared via hot pressing, hot deformation, spark plasma sintering, and other consolidation processes, which are typically performed at 400–500 °C. Such high-temperature processes are energy-intensive and generate unnecessary waste heat, making them undesirable for a large-scale production. In this study, a low-temperature liquid-phase-assisted sintering (or so-called cold-sintering) process was employed to fabricate p-type Bi0.5Sb1.5Te3 bulk materials at temperatures below 150 °C. At the optimal sintering temperature (130 °C), a ZT value as high as 0.56 at 450 K can be achieved, competitive to that of a commercial Bi0.5Sb1.5Te3 ingot (ZT 0.8–1.0). The addition of a small amount of transient liquid facilitates grain reorientation and expedites a mass transfer process under axial compaction and liquid evaporation conditions, thus resulting in nearly fully densified Bi0.5Sb1.5Te3 pellet samples (>97% theoretical density). Furthermore, the low-temperature sintering process results in the reduction of grain size and promotes twin boundaries, resulting in a low lattice thermal conductivity of 0.57 W m–1 K–1 at 380 K due to phonon scattering. The strategy reported in this work can be used not only as a substitute for high-temperature sintering of other thermoelectric materials but also to engineer phonon scattering for high-performance thermoelectrics.

The lithium-ion battery has the advantages of high energy density, long cycle life, small occupied volume, and high discharge voltage, which significantly promotes the development of portable electronic devices and...

Due to the high theoretical lithium storage capacity and moderate voltage platform, silicon is expected to substitute graphite and serves as the most promising anode material for lithium-ion batteries (LIBs). However, substantial volume change during cycling subjects the silicon anode to electrode pulverization and conductive network damage, extensively limiting its commercial purpose. Strategies, such as alloying, nano-crystallization, and compositing, are developed against these problems. This review introduces the attractive alloying modification method and summarizes the recent advances in microstructureengineered silicon alloy anodes for LIBs. The electrochemical performances of silicon alloy anodes with various morphologies, such as nanoparticles, nanowires, two-dimensional layered structures, porous structures, and thin films, are discussed in detail. The challenges for the commercial application of silicon alloy anodes are elaborated in the end. This review provides a comprehensive overview and concerns of microstructure-engineered silicon alloy anodes for potential applications in LIBs.