Potential of Recycled Silicon and Silicon-Based Thermoelectrics for Power Generation

Abstract

Thermoelectrics can convert waste heat to electricity and vice versa. The energy conversion efficiency depends on materials figure of merit, zT, and Carnot efficiency. Due to the higher Carnot efficiency at a higher temperature gradient, high-temperature thermoelectrics are attractive for waste heat recycling. Among high-temperature thermoelectrics, silicon-based compounds are attractive due to the confluence of light weight, high abundance, and low cost. Adding to their attractiveness is the generally defect-tolerant nature of thermoelectrics. This makes them a suitable target application for recycled silicon waste from electronic (e-waste) and solar cell waste. In this review, we summarize the usage of high-temperature thermoelectric generators (TEGs) in applications such as commercial aviation and space voyages. Special emphasis is placed on silicon-based compounds, which include some recent works on recycled silicon and their thermoelectric properties. Besides materials design, device designing considerations to further maximize the energy conversion efficiencies are also discussed. The insights derived from this review can be used to guide sustainable recycling of e-waste into thermoelectrics for power harvesting.

Harnessing Ash for Sustainable CO2 Absorption: Current Strategies and Future Prospects

“…It is a hot topic of waste recycling and upcycling in recent years due to more awareness of the environmental sustainability of the entire society. [153][154][155][156] Transforming burnt ash into a material for capturing CO 2 is not only an efficient method of recycling waste but also addresses a crucial ecological issue arising from ash disposal. This is significant given the urgent need to address rising global temperatures and climate change impacts.…”

Recent Progress in Polyethylene‐enhanced Organic Phase Change Composite Materials for Energy Management

“…Because the PCMs remains at their temperature during the phase change process until all the materials complete the phase change. Thus, researchers are attracted to explore PCMs for thermal energy storage to make efficient use of waste heat [165–168] . They introduce various additives to enhance thermal properties of PCMs, such as thermal conductivity and stability, with the aim to increase PCMs efficacy in storing thermal heat.…”

“…Thus, researchers are attracted to explore PCMs for thermal energy storage to make efficient use of waste heat. [165][166][167][168] They introduce various additives to enhance thermal properties of PCMs, such as thermal conductivity and stability, with the aim to increase PCMs efficacy in storing thermal heat.…”

Recent Advances in the Nanomaterials, Design, Fabrication Approaches of Thermoelectric Nanogenerators for Various Applications

“…Moreover, because silicon waste has been increasing with technological advancement, recycling silicon for TENG applications has been explored. [17,127,128] Figure 7 illustrates how Liu et al [17] reused silicon waste and enhanced it with alloying and doping to outperform commercially available bulk silicon-based TE materials. As a TE material, silicon is promising for near-room-temperature applications with a high Seebeck coefficient and electrical conductivity, lending it to higher PFs of up to 15 mW K −2 m −1 at room temperature.…”

“…Moreover, because silicon waste has been increasing with technological advancement, recycling silicon for TENG applications has been explored. [ 17,127,128 ] Figure illustrates how Liu et al. [ 17 ] reused silicon waste and enhanced it with alloying and doping to outperform commercially available bulk silicon‐based TE materials.…”