Highly Efficient CO2 Utilization via Molten Salt CO2 Capture and Electrochemical Transformation Technology

doi:10.13208/j.electrochem.200653

Abstract

Abstract:

The molten electrolytes exhibit high CO₂ absorption capacities, wide electrochemical windows and excellent reaction kinetics, which are promising electrolyte candidates for efficient capture and electrochemical conversion of high-flux CO₂ driven by renewable and clean electricity sources. This short review introduces the recent advancements of CO₂ electroreduction achieved by the authors using molten salt CO₂ capture and electrochemical transformation (MSCC-ET) technology, involving CO₂ absorption kinetics, cathodic kinetics, controllable synthesis of carbon products with unique nanostructures, development of inert oxygen evolution anodes and CO₂ conversion efficiency as well as energy efficiency. The challenges and prospects are also discussed based on the critical review.

Key words: molten electrolytes, CO₂ reduction, cathodic kinetics, carbon materials, inert anode, MSCC-ET

CLC Number:

O646

DENG Bo-wen, YIN Hua-yi, WANG Di-hua. Highly Efficient CO₂ Utilization via Molten Salt CO₂ Capture and Electrochemical Transformation Technology[J]. Journal of Electrochemistry, 2020, 26(5): 628-638.

Figures/Tables 9

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References 43

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Electrolyte	Equilibrium pressure of CO₂/ (Pa, aM_yO=0.001 mol·L^-1)	Deposition potential of metal E_M/V(vs. CO₂-O₂/CO₃^2-)	Deposition potential of C E_C/V(vs. CO₂-O₂/CO₃^2-)	Evolution potential of CO E_CO/V(vs. CO₂-O₂/CO₃^2-)
Li₂CO₃	1.039	-3.183	-1.883	-2.284
Na₂CO₃	2.462×10^-8	-2.757	-2.681	-3.378
K₂CO₃	2.054×10^-13	-2.829	-3.251	-4.107
CaCO₃	2.309×10³	-3.230	-1.523	-1.804
BaCO₃	1.793×10^-3	-3.266	-2.181	-2.681

T/^oC	ΔG/(kJ·mol^-1) 2Li₂CO₃=2CO(g)+O₂(g)+Li₂O	E_CO/V	ΔG/(kJ·mol^-1) Li₂CO₃=C+O₂(g)+Li₂O	E_C/V	Energy consumption/(kWh·kg^-1-C)@50%EE
50	855.157	2.216	566.998	1.469	26.25
450	660.625	1.712	505.931	1.311	23.42
750	527.734	1.367	466.199	1.208	21.58

Electricity source	*Average amount of equivalent CO₂ emission in 50th percentile^[43]/(g·kWh^-1)	CO₂ reduction efficiency/% (6.4 kWh·kg^-1-CO₂@50%EE)
Hydroelectric	4	97.44
Wind	12	92.32
Nuclear	16	89.76
Biomass	18	88.48
Solar thermal	22	85.92
Geothermal	45	71.20
Solar PV	46	70.56

Highly Efficient CO₂ Utilization via Molten Salt CO₂ Capture and Electrochemical Transformation Technology

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