title: Harvesting waste thermal energy using a carbon-nanotube-based thermo-electrochemical cell.
abstract: Low efficiencies and costly electrode materials have limited harvesting of thermal energy as electrical energy using thermo-electrochemical cells (or "thermocells"). We demonstrate thermocells, in practical configurations (from coin cells to cells that can be wrapped around exhaust pipes), that harvest low-grade thermal energy using relatively inexpensive carbon multiwalled nanotube (MWNT) electrodes. These electrodes provide high electrochemically accessible surface areas and fast redox-mediated electron transfer, which significantly enhances thermocell current generation capacity and overall efficiency. Thermocell efficiency is further improved by directly synthesizing MWNTs as vertical forests that reduce electrical and thermal resistance at electrode/substrate junctions. The efficiency of thermocells with MWNT electrodes is shown to be as high as 1.4% of Carnot efficiency, which is 3-fold higher than for previously demonstrated thermocells. With the cost of MWNTs decreasing, MWNT-based thermocells may become commercially viable for harvesting low-grade thermal energy.
authors.affiliation: Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75083, USA.
authors.forename: Renchong
authors.initials: R
authors.lastname: Hu
authors.forename: Baratunde A
authors.initials: BA
authors.lastname: Cola
authors.forename: Nanda
authors.initials: N
authors.lastname: Haram
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Barisci
authors.forename: Sergey
authors.initials: S
authors.lastname: Lee
authors.forename: Stephanie
authors.initials: S
authors.lastname: Stoughton
authors.forename: Gordon
authors.initials: G
authors.lastname: Wallace
authors.forename: Chee
authors.initials: C
authors.lastname: Too
authors.forename: Michael
authors.initials: M
authors.lastname: Thomas
authors.forename: Adrian
authors.initials: A
authors.lastname: Gestos
authors.forename: Marilou E Dela
authors.initials: ME
authors.lastname: Cruz
authors.forename: John P
authors.initials: JP
authors.lastname: Ferraris
authors.forename: Anvar A
authors.initials: AA
authors.lastname: Zakhidov
authors.forename: Ray H
authors.initials: RH
authors.lastname: Baughman
mesh_terms: D003460:Crystallization / Q000379:methods; D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation*; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D008422:Materials Testing; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size
chemical_list: D037742:Nanotubes, Carbon