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Sains Malaysiana 47(2)(2018):
403-408
http://dx.doi.org/10.17576/jsm-2018-4702-23
The Role of Electrolyte Fluidity on The Power Generation
Characteristics of Thermally Driven Electrochemical Cells
(Peranan Kebendaliran Elektrolit pada Ciri-ciri Penjanaan Kuasa
bagi Sel Elektrokimia Terpacu Haba)
Syed
Waqar Hasan1, Suhana Mohd Said1*, Ahmad Shuhaimi Bin Abu
Bakar2, Hasan Abbas Jaffery3 & Mohd. Faizul Mohd. Sabri3
1Department of Electrical Engineering,
University of Malaya, 50603 Kuala Lumpur, Federal
Territory, Malaysia
2Low Dimensional Materials Research
Centre, Department of Physics, 50603 Kuala Lumpur, Federal
Territory, Malaysia
3Department of Mechanical Engineering,
University of Malaya, 50603 Kuala Lumpur, Federal Territory, Malaysia
Diserahkan:
7 April 2017/Diterima: 8 Ogos 2017
ABSTRACT
Thermally
driven electrochemical cells (thermocells) are able to convert thermal gradient
applied across redox electrolyte into electricity. The performance of the
thermocells heavily depends on the magnitude and integrity of the applied
thermal gradient. Herein, we study the iodide/triiodide (I‾/I3‾) based 1-Ethyl-3-methyl-imidazolium
Ethylsulfate ([EMIM][EtSO4])
solutions in a thermocell. In order to comprehend the role of fluidity of the
electrolyte, we prepared set of solutions by diluting [EMIM][EtSO4]
with 0.002, 0.004, and 0.010 mol of Acetonitrile (ACN). We realized a significant improvement in ionic conductivity (s) and electrochemical Seebeck (Se) of diluted electrolytes as compared to base [EMIM][EtSO4]
owing to the solvent organization. However, the infra-red thermography
indicated faster heat flow in ACN-diluted-[EMIM][EtSO4]
as compared to the base [EMIM][EtSO4]. Therefore, the maximum power
density of base [EMIM][EtSO4] (i.e. 118.5 mW.m-2) is 3 times higher than the ACN-diluted-[EMIM][EtSO4] (i.e. 36.1 mW.m-2) because of the lower thermal conductivity. Hence this
paper illustrates the compromise between the fast mass/flow transfer due to
fluidity (of diluted samples) and the low thermal conductivity (of the pure
[EMIM][EtSO4]).
Keywords:
Electrochemical cells; energy harvesting; ionic liquids; redox couple;
thermoelectrics
ABSTRAK
Sel elektrokimia yang dipacu secara haba (termosel)
dapat menukar kecerunan terma yang digunakan merentasi elektrolit redoks ke
dalam elektrik. Prestasi termosel sangat bergantung pada magnitud dan integriti kecerunan terma yang digunakan. Di sini, kami mengkaji larutan iodide/triiodide (I‾/I3‾) berasaskan 1-Ethyl-3-methyl-imidazolium
Ethylsulfate ([EMIM][EtSO4])
dalam termosel. Bagi memahami peranan ketidakstabilan elektrolit, kami
menyediakan satu set larutan dengan mencairkan [EMIM][EtSO4] dengan
0.002, 0.004, dan 0.010 mol Acetonitrile (ACN). Didapati bahawa peningkatan yang ketara dalam kekonduksian ion (s) dan elektrokimia Seebeck (Se) daripada
elektrolit yang dicairkan berbanding dengan asas [EMIM][EtSO4]
disebabkan oleh organisasi pelarut. Namun, termografi infra-merah menunjukkan
bahawa aliran haba yang lebih cepat di dalam ACN-dicairkan-[EMIM][EtSO4]
berbanding dengan asas [EMIM][EtSO4]. Oleh itu, ketumpatan kuasa
maksimum asas [EMIM][EtSO4] (iaitu 118.5 mW.m-2) adalah 3 kali lebih tinggi daripada ACN-dicairkan-[EMIM][EtSO4] (iaitu 36.1 mW.m-2) akibat daripada kekonduksian terma yang lebih rendah. Dengan ini, kajian ini menggambarkan kompromi antara pemindahan jisim/aliran cepat
disebabkan oleh kecairan (sampel yang dicairkan) dan kekonduksian haba yang
rendah (bagi [EMIM][EtSO4] tulen).
Kata
kunci: Cecair ionik; pasangan redox; penuaian tenaga; sel elektrokimia;
termoelektrik
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*Pengarang untuk surat-menyurat; email: smsaid@um.edu.my
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