Development and characterization of bi-functional air electrodes for rechargeable zinc-air batteries: Effects of carbons

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• 作者：Po-Chieh Li ; Chi-Chang Hu ; ^{cchu@che.nthu.edu.tw" class="auth_mail" title="E-mail the corresponding author} ; ; Ting-Hsuan You ; Po-Yu Chen
• 关键词：Rechargeable zinc&ndash ; air battery ; α-MnO2/carbon composites ; Multiwalled carbon nanotubes ; Charge&ndash ; discharge cycle
• 刊名：Carbon
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：111
• 期：Complete
• 页码：813-821
• 全文大小：2170 K

文摘

In spite of high mean transfer number and catalytic ability of the oxygen reduction reaction (ORR), α-MnO₂ is lack of electric conductivity and specific surface area to fully exert the performance of rechargeable Zn-air battery. Here, carbons in various forms are chosen as substrates for uniform dispersion of α-MnO₂ to form air electrode catalysts to evaluate the influences of carbon types on the catalytic activities of the ORR and OER (oxygen evolution reaction). The morphology and physicochemical properties of various α−MnO₂/carbon composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Electrochemical studies include rotating ring-disk electrode (RRDE) voltammetry of catalysts, linear sweep voltammetry (LSV) of air electrodes, and the charge-discharge-cycling test of full cells. The discharge peak power density of Zn-air batteries varies from 66.3 (α−MnO₂/carbon nanotubes with diameter ≈10 nm, denoted as α−MnO₂/CNT10) to 40.5 mW cm⁻² (α−MnO₂/super fine mesophase graphite powder) in 6 M KOH under ambient condition. The rechargeable Zn-air battery with the air electrode containing α−MnO₂/CNT10 is stably operated for 100 cycles at 10 mA cm⁻², which shows that an increase in 0.09 V between charge (decayed ca. 0.05 V) and discharge (decayed ca. 0.04 V) cell voltages.