Current density dependence on performance degradation of direct methanol fuel cells

Jeon, Min Ku; Lee, Ki Rak; Oh, Kyoung‐Sub; Hong, Dae Sun; Jung, Won Seok; Li, Shuang; Woo, Seong Ihl

doi:10.1016/j.jpowsour.2005.10.056

Cited by 64 publications

(32 citation statements)

References 11 publications

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“…ARR increased by 0.003 (3%), from 0.097 to 0.10 , after the stability test. This small change of ARR is an interesting result because significant changes such as agglomeration of catalyst and dissolution of Ru were observed in previous reports [2,3]. Further investigation on the anode catalyst was shown in the last part of this section.…”

Section: Resultssupporting

confidence: 76%

“…In our previous report, degradation of membrane by removal of SO 3 H + from Nafion TM membrane was observed [2]. The increase of equivalent weight by removal of SO 3 H + must be one of the main reasons of the large increase of IR resistance observed in this study.…”

Section: Resultssupporting

confidence: 52%

“…We reported operation current density dependence of DMFC where maximum power density decreased to 55% of the initial value after operation at 200 mA cm −2 for 145 h [2]. Liu et al [3] reported 30% decrease of maximum power density after operation at 100 mA cm −2 for 75 h. Dissolution and crossover of Ru from anode to cathode, agglomeration of catalysts, chemical degradation of membrane and water flooding in cathode were pointed out as key components of the performance degradation [4][5][6][7].…”

Section: Introductionmentioning

confidence: 94%

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Performance degradation study of a direct methanol fuel cell by electrochemical impedance spectroscopy

Jeon

Jung

et al. 2007

Electrochimica Acta

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Section: Resultssupporting

confidence: 76%

Section: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 94%

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Performance degradation study of a direct methanol fuel cell by electrochemical impedance spectroscopy

Jeon

Jung

et al. 2007

Electrochimica Acta

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“…I FC is sufficiently small (at 0.5 mA) to avoid stressing the FC's membrane electrode assembly beyond its rating (for overload protection) and high enough to reduce the percentage of fuel lost through the membrane as leakage (for load matching) [24][25][26]. I LI is higher at 2.5 mA to supply the heavier loads that the small FC cannot.…”

Section: Power Mixermentioning

confidence: 99%

Single-inductor fuel cell-Li ion charger-supply IC with nested hysteretic control

Kim

Rincón-Mora

2011

Analog Integr Circ Sig Process

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Microsystems must conform to microscale dimensions, store sufficient energy to last extended periods, and supply enough power to sustain, among others, wireless and sensor functions. Because batteries source moderate power with low energy densities, miniaturized devices benefit from deriving energy from fuel cells (FCs) and power from Li ions, rather than relying on one source and over-sizing it to offset its deficiency. This article presents a single-inductor, dual-input, dual-output (SIDIDO) charger-supply 0.5-lm CMOS IC with a nested hystereticcontrol scheme that draws energy from a FC and conditions power to charge a Li ion and supply a 1-V, 1-mA load. The IC dynamically adjusts to the load, charging the Li ion with excess power from the FC during light loads and supplying power from both the FC and Li ion otherwise. The fabricated prototype regulated its output to 1 V within 2.5% and responded to rising and falling 0.1-1-mA load dumps within 30 ls and 50 mV. The efficiency peaked at 32% because the load was low and the converter operated in continuous (rather than in discontinuous) conduction and sensed its inductor current via lossy sense resistors (instead of sense FETs) to manage risk and validate functionality.Keywords Single inductor Á Hybrid source Á Switching converter IC Á Fuel cell Á Hysteretic control 1 Battery-powered microsystems Advances in silicon and MEMS technologies are paving the way for smart, non-intrusive, and battery-powered microscale devices, such as wireless microsensors, whose impact on military, space, industrial, and biomedical applications [1-3] is to increase functionality (e.g., monitoring), improve performance (with dynamic control), and lower energy use (with in situ intelligence). Powering these systems under such space constraints is challenging because batteries do not supply sufficient energy to last the lifetime demanded of them and fuel cells (FCs), atomic batteries, and harvesters do not source enough power to enable critical functions like telemetry and sensor-interface blocks. What is more, these devices must mode-hop between idle and other states to conserve energy, requiring their supplies to adjust and source diverse load levels [4, 5]. Hybrid sourcesPower and energy densities do not correlate in microscale sources. Nuclear batteries and FCs, for example, are energy dense but supply little power when compared to other equally sized sources [6][7][8]. In other words, these technologies outlast others when they supply little power but quickly outlive their usefulness when loaded beyond their capacities. In contrast, Li-Ion batteries store less energy but produce higher power, that is, source higher energy when supplying higher power under equivalent space constraints. However, over-sizing the battery (or FC) to meet energy (or power) demands is not functionally efficient in microscale applications. As a result, mixing complementary technologies like FCs and Li ions offers a considerable advantage in size [9], which is why research in this area (as in portable [10] a...

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“…[1][2][3][4][5] Significant and intensive investigations in this field have been progressed to commercialize this device. Until now, all low-temperature fuel cells including DMFCs have used platinum or platinum based materials as the electrode.…”

Section: Introductionmentioning

confidence: 99%

Polyol Synthesis of Ruthenium Selenide Catalysts for Oxygen Reduction Reaction

Lee¹,

Woo²

2010

Bulletin of the Korean Chemical Society

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Ruthenium catalysts modified by selenium have been introduced as alternative materials to Pt in Direct methanol fuel cells (DMFCs). RuSe nano-particles were synthesized on the Vulcan XC72R carbon supports via polyol method. The prepared catalysts were electrochemically and physically characterized by cyclic voltammetry (CV,) linear sweep voltammetry, methanol tolerance test, X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energydispersive Spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Increasing the Se concentration up to 20 at % increased the electro-catalytic activity for the oxygen reduction. By increasing Se amount, Ru metallic form on the surface was increased. The Ru80Se20/C catalysts showed the highest oxygen reduction reaction (ORR) activity and outstanding methanol tolerant property in half cell tests as well as single cell test.

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Current density dependence on performance degradation of direct methanol fuel cells

Cited by 64 publications

References 11 publications

Performance degradation study of a direct methanol fuel cell by electrochemical impedance spectroscopy

Performance degradation study of a direct methanol fuel cell by electrochemical impedance spectroscopy

Single-inductor fuel cell-Li ion charger-supply IC with nested hysteretic control

Polyol Synthesis of Ruthenium Selenide Catalysts for Oxygen Reduction Reaction

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