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

 

Received: 7 April 2017/Accepted: 8 August 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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*Corresponding author; email: smsaid@um.edu.my

 

 

 

 

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