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Thermo-osmotic energy conversion (TOEC) technology, developed from membrane distillation, is an emerging method that has the potential of obtaining electricity efficiently from a low-grade heat source but faces the difficult problem of pump power loss. In this study, we build a novel TOEC system with a multistage architecture that can work without pump assistance. The experiment system, made of cheap commercial materials, can obtain a power density of 1.39 ± 0.25 W/m 2 , with a heating temperature of 80 °C, and its efficiency increased linearly with the total stage number. A theory calculation shows that a 30-stage system with a specific membrane and a working pressure of 5.0 MPa can obtain an efficiency of 2.72% with a power density of 14.0 W/m 2 . By a molecular dynamics simulation, it is shown that a high-performance membrane has the potential to work at 40 MPa. This study proves that TOEC technology is a practical and competitive approach to covert low-grade thermal energy into power efficiently.

Bulk polymers are often regarded as thermal insulators due to low thermal conductivity, which extremely limits their applications in the field of heat transfer. Over the past decades, thermal transport in polymers, and polymer nanocomposites has been intensively studied on both theoretical and experimental levels. In addition, novel thermal transport phenomenon involving divergent thermal conductivity in individual polymer chains, giant thermal rectification, has been observed. In this review, the mechanism behind thermal transport in materials, interfacial thermal transport, thermal rectification in polymers, and enhancing thermal transport of polymers are firstly addressed. Secondly, the computational methods for investigating the thermal property of materials mainly focused on molecular dynamics (MD) simulation are summarized and compared. The advanced spectral decomposition methods in non-equilibrium molecular dynamics (NEMD) simulation are highlighted. Thirdly, experimental advances relevant to thermal transport of polymers are briefly reviewed. Finally, the challenges and outlook about modulating thermal transport in polymers and polymer nanocomposites are pinpointed.

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