Researchers at the Institute of Chemistry of the Chinese Academy of Sciences, led by academician Zhu Daoben and researcher Di Zhong'an, have announced a materials breakthrough that pushes flexible polymer thermoelectric films into a new performance regime. By engineering an irregular, multiscale porous structure in a polymer film via a ‘‘polymer phase separation’’ process, the team reports a thermoelectric figure of merit (zT) of 1.64 — a value that, if sustained under real‑world conditions, would be a world record for flexible materials in the same temperature window.
The figure of merit zT combines electrical conductivity, the Seebeck coefficient and thermal conductivity into one number that gauges conversion efficiency of heat into electricity; values above unity are widely regarded as the threshold for practical thermoelectric applications. For decades, high‑zT materials have been largely brittle inorganic alloys or nanostructured ceramics, such as bismuth telluride, which complicate use in wearable or conformable devices. A polymer film with zT exceeding 1.5 would mark a historic shift: light, flexible, spray‑coatable plastics could become viable energy harvesters.
The technical route the team used matters as much as the number. The phase‑separation method yields an irregular, hierarchical pore network and can be processed in a single step compatible with spray‑coating, the researchers say — a manufacturing advantage over multilayer deposition or vacuum‑based techniques. That lowers barriers to scaling and to integrating thermoelectric films onto curved surfaces, textiles or thin patches where conventional rigid modules cannot go.
Potential applications are familiar to technologists but have so far been constrained by materials limits: wearable electronics that scavenge body heat, adhesive cooling patches that pump heat away from hotspots, and distributed sensors for the internet of things that run on small temperature gradients. Because polymers eschew many of the scarce or toxic elements used in inorganic thermoelectrics, a polymer‑based route could also ease supply‑chain and environmental concerns if the performance holds up through device integration and over time.
Caveats remain substantial. Laboratory zT measurements do not automatically translate to useful electrical power at the small temperature differentials typical of human skin or ambient waste‑heat streams. Long‑term mechanical durability, stability under humidity and temperature cycles, and the film’s power factor (the product of electrical conductivity and Seebeck coefficient) when scaled to practical thicknesses are all open questions. Integration challenges — contacts, thermal interfaces, and packaging — will determine whether the material becomes a commercial product or a notable but niche scientific result.
Even so, this development is significant on two fronts: it advances fundamental understanding of heat and charge transport in so‑called soft matter, and it signals growing Chinese strength in advanced functional materials. If the manufacturing claims are borne out, spray‑coatable thermoelectric films could accelerate experimentation and commercial prototyping worldwide, making small, distributed heat harvesting more feasible and nudging waste heat up the priority list of renewable energy strategies.