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Title: Continuous electrochemical heat engines

Journal Article · · Energy & Environmental Science
DOI: https://doi.org/10.1039/c8ee01137k · OSTI ID:1490884
 [1];  [2]; ORCiD logo [3]; ORCiD logo [4]
  1. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Stanford Univ., Stanford, CA (United States)
  3. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Precourt Institute for Energy, Stanford, CA (United States)
  4. Stanford Precourt Institute for Energy, Stanford, CA (United States); Stanford Univ., Stanford, CA (United States)

Given the large magnitude of energy in waste heat, its efficient conversion to electrical power offers a significant opportunity to lower greenhouse gas emissions. Furthermore, it has been difficult to optimize the performance of new direct energy conversion approaches because of the coupling between entropy change and thermal and electrical transport in continuously operating devices. With electrochemical cells driving flowing electrolytes in symmetric redox reactions at different temperatures, we demonstrate two continuous electrochemical heat engines that operate at 10–50 °C and at 500–900 °C, respectively. Simulations of kilowatt-scale systems using electrochemical cells stacked in series suggest efficiencies over 30% of the Carnot limit and areal power densities competitive with solid-state thermoelectrics at maximum power. Although entropy change, thermal transport and electrical transport are inherently coupled in solid-state thermoelectrics, they can be somewhat circumvented in electrochemical systems, thus offering new opportunities to engineer efficient energy conversion systems.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1490884
Alternate ID(s):
OSTI ID: 1461903
Journal Information:
Energy & Environmental Science, Journal Name: Energy & Environmental Science Journal Issue: 10 Vol. 11; ISSN EESNBY; ISSN 1754-5692
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (2)

Electrochemical Redox Refrigeration journal September 2019
Direct thermal charging cell for converting low-grade heat to electricity journal September 2019