Thermally regenerative copper nanoslurry flow batteries for heat-to-power conversion with low-grade thermal energy

Abstract

Thermally charging all-copper batteries with high cell voltage and output power enabling heat-to-power conversion and storage.

Thermally regenerative electrochemically cycled flow batteries with pH neutral electrolytes for harvesting low-grade heat

“…Figure 8b 24,53 thermally regenerative electrochemical cycles (TREC), [25][26][27] vacuum distillation -concentration redox flow battery (VD-CRFB), 21,22 vacuum distillation/membrane distillation -reverse electrodialysis (VD/MD-RED), 54,55 thermolysisreverse electrodialysis (TL-RED), 56 vacuum distillation/membrane distillation-pressure retarded osmosis (VD/MD-PRO), 57,58 thermo-osmosis energy conversion (TOEC), 59 thermally charged batteries including thermally regenerative ammonia battery (TRAB), [12][13][14][15][16][17][18][19] thermally regenerative copper acetonitrile battery (CuACN). 20 To provide insights for future improvement of power density and higher efficiency, it is important to understand the factors contributing to the overpotential as an irreversible loss. Such irreversible loss is especially important when the flow rate is small, manifested in the clear deviation of the voltage drop from the linear voltage-current ( ) relation at a large discharge current (Figure 5a).…”

“…This recent pursuit is because the "effective thermopower" (on the order of 1 to 10 mV/K) [2][3][4][5] is relatively high compared with thermoelectric materials (~ 200 μV/K). 6 Several different types of devices have been investigated, [7][8][9] including thermionic capacitors, 10,11 thermally charged batteries, [12][13][14][15][16][17][18][19][20] , vacuum distillation -concentration redox flow battery (VD-CRFB), 21,22 thermogalvanic cells, 23,24 thermally regenerative electrochemical cycles (TREC) [25][26][27] and thermally regenerative electrochemically cycled flow batteries (TREC-FB) 28,29 . Thermionic capacitors rely on the thermodiffusion of ions, also known as the Soret effect.…”

“…Heat conduction leakage along with the long thermal charging time has led to low efficiency (0.01%). 5,30 Thermally regenerable batteries utilize electrolytes that can be regenerated using heat, including copper-ammonia battery [12][13][14] , copper-ethylenediamine battery 15 , and copper-acetonitrile batteries 20 . The discharge power density of these thermally charged batteries can reach 10 W/m 2 K to 100 W/m 2 K and have a high efficiency (15%~30% relative to the Carnot limit).…”

Thermally Regenerable Redox Flow Battery

“…One of the most recent technology proposed to convert low‐temperature heat into electrical energy, is TRCB, redox‐flow cell in which power generation is related to the metal‐complexes formation (Cu or Ag with acetonitrile or ammonia). The solutions are then regenerated by distillation of ammonia or acetonitrile …”

“…The solutions are then regenerated by distillation of ammonia or acetonitrile. [36][37][38][39] TRCBs have several advantages such as a simple and easily scalable setup and need relatively inexpensive reactants and electrode materials. [22] However, TRCBs exploit much smaller temperature differences compared to the other technologies here reported, resulting in lower thermal-energy efficiency.…”