Introducing catalyst in alkaline membrane for improved performance direct borohydride fuel cells

Abstract

H I G H L I G H T S• Catalyst was introduced in composite alkaline membrane uses as electrolyte for DBFC.• Addition of catalyst increased ionic conductivity of membrane.• Addition of catalyst reduced fuel cross-over and electrode polarization.• DBFC using that membrane achieved OCV 1.11 V and P max = 166 mW cm −2 at 30°C.• Idea of adding catalyst in membrane may apply in other electrochemical devices. G R A P H I C A L A B S T R A C T A R T I C L E I N F O Keywords:Alkaline polymer electrolyte membrane Direct borohydride fuel cell Ionic conductivity Performance Electrochemical impedance spectroscopy A B S T R A C TA catalytic material is introduced into the polymer matrix to prepare a novel polymeric alkaline electrolyte membrane (AEM) which simultaneously increases ionic conductivity, reduces the fuel cross-over. In this work, the hydroxide anion exchange membrane is mainly composed of poly(vinylalcohol) and alkaline exchange resin. CoCl 2 is added into the poly(vinylalcohol) and alkaline exchange resin gel before casting the membrane to introduce catalytic materials. CoCl 2 is converted into CoOOH after the reaction with KOH solution. The crystallinity of the polymer matrix decreases and the ionic conductivity of the composite membrane is notably improved by the introduction of Co-species. A direct borohydride fuel cell using the composite membrane exhibits an open circuit voltage of 1.11 V at 30°C, which is notably higher than that of cells using other AEMs. The cell using the composite membrane achieves a maximum power density of 283 mW cm −2 at 60°C while the cell using the membrane without Co-species only reaches 117 mW cm −2 at the same conditions. The outstanding performance of the cell using the composite membrane benefits from impregnation of the catalytic Co-species in the membrane, which not only increases the ionic conductivity but also reduces electrode polarization thus improves the fuel cell performance. This work provides a new approach to develop high-performance fuel cells through adding catalysts in the electrolyte membrane.

Electricity Generation from Ammonia in Landfill Leachate by an Alkaline Membrane Fuel Cell Based on Precious-Metal-Free Electrodes

“…The size of the 1 × 1 cm 2 carbon paper covered by catalyst was used in the following fuel cell tests. The alkaline membrane was prepared from AER (Amberlite IRA-402­(OH), hydroxide form, Alfa Aesar) and PVA (MW 57 000–66 000, Alfa Aesar) at a weight ratio of 1:2, according to the method described in a previous paper . The effective area of the alkaline membrane fuel cell was 1 × 1 cm 2 .…”

Alkaline membrane fuel cells: anion exchange membranes and fuels

“…It yielded a peak power density of 321 mW cm À2 at 40 C with oxygen as the cathode feed and a fuel feed comprised of 1 M NaBH 4 and 3 M NaOH (Pt/C was utilised as the cathode and anode catalyst). Qin et al 214 introduced a novel hydroxide anion exchange membrane composed mainly of poly(vinyl alcohol) and alkaline exchange resin (PVA-AER), and the same membrane impregnated with Co (Co-impregnated PVA-AER). The testing conditions were the same for both types of membrane, being, 5 wt% NaBH 4 and 10 wt% NaOH at 60 C as fuel, and humidied oxygen with a back-pressure of 0.2 MPa as the cathode feed.…”

Cobalt nickel boride nanocomposite as high-performance anode catalyst for direct borohydride fuel cell

“…Hydrogen fueled polymer electrolyte membrane fuel cell (PEMFC) with zero carbon emission is considered as a promising renewable energy source for environmental 3 remedy [1,2]. However, hydrogen as fuel imposes storage and transportation risk [3,4].…”

“…Direct borohydride fuel cell (DBFC) by employing KBH4 solution as fuel, overcomes these issues and concomitantly provides high theoretical open-circuit potential (OCP) of 1.64 V due to high hydrogen content of KBH4 (7.5 wt%) and its high energy density (6500 Wh/kg) [5]. As shown in Eq (1), the maximum of eight electrons are released during borohydride electrooxidation reaction (BOR) on the DBFC anode side [6].…”