Output Current Density Research Articles

Breaking dielectric dilemma via polymer functionalized perovskite piezocomposite with large current density output

Organometal halide perovskite (OHP) composites are flexible and easy to synthesize, making them ideal for ambient mechanical energy harvesting. Yet, the output current density from the piezoelectric nanogenerators (PENGs) remains orders of magnitude lower than their ceramic counterparts. In prior composites, high permittivity nanoparticles enhance the dielectric constant (ϵr) but reduce the dielectric strength (Eb). This guides our design: increase the dielectric constant by the high ϵr nanoparticle while enhancing the Eb by optimizing the perovskite structure. Therefore, we chemically functionalize the nanoparticles to suppress their electrically triggered ion migration for an improved piezoelectric response. The polystyrene functionalizes with FAPbBr2I enlarges the grains, homogenizes the halide ions, and maintains their structural integrity inside a polymer. Consequently, the PENG produces a current density of 2.6 µAcm−2N−1. The intercalated electrodes boost the current density to 25 µAcm−2N−1, an order of magnitude enhancement for OHP composites, and higher than ceramic composites.

Numerical investigation of PEMFC performance based on different multistage serpentine flow field designs

The design of excellent flow fields can significantly enhance the output current density and improve the uniformity of reactant distribution in PEMFC (Proton Exchange Membrane Fuel Cell). Serpentine flow field has gained more attention due to its outstanding performance and simple structure, but there is little research on multi-channel serpentine flow field considering the consumption of reactant. In this paper, flow fields named multi-s and multi-pis were designed by considering reactant consumption, and compared with the traditional serpentine flow fields including 3 s, 5 s, 3pis and 5pis. Compared with 3 s and 5 s, the average power density of multi-s increased by 0.687 % and 1.256 %, respectively. The average power density of multi-pis increased by 0.326 % and 1.829 %, as compared to that of 3pis and 5pis. Moreover, the utilization of multiple serpentine and parallel flow fields enhances the uniformity of reactant distribution and current density. The paper further investigates the impact of inlet humidity, operating temperature and supply back pressure on the performance of these six flow fields at a working voltage of 0.45 V. The variations of operating parameters exert varying degrees of influence on the different flow fields, multi-s and multi-pis flow fields consistently demonstrating superior performance to the other four flow fields. The present study offers practical guidance for the implementation of PEMFCs, encompassing optimization strategies for flow field design, operation.

Tribo-hygro-electric generator: Harnessing mechanical energy with liquid-infused porous cellulose for multiple sensing and DC power generation

This study introduces the Tribo-Hygro-Electric Generator (THEG), a novel device that harvests ambient mechanical and water-enabled energies for highly sensitive, self-powered multi-sensing. THEG employs a simple design using liquid-infused porous cellulose (LIPC), created by absorbing functional liquids such as water into porous cellulose, and metal contacts with distinct work functions (e.g., Al and Cu) to generate triboelectric charges through friction. It operates via a three-step process: generating triboelectric charges through sliding motion, establishing an internal electric field across Al/LIPC/Cu interfaces for charge separation, and directing charges to create unidirectional output electron transfer, producing direct current (DC) outputs. The principle behind THEG emphasizes the critical role of the single Schottky contact at the Al/LIPC interface in separating and directing charge transfer, as well as the conductive path formed by the hydrogen-bonded network of water molecules and cellulose’s functional groups. THEG can harvest DC power with a current density of up to 3.4 A/m² and 0.5 V, which can be increased to 2 V with four cells in series. THEG demonstrates impressive multiple-sensing capabilities, with robust linear relationships (correlation coefficients > 0.99) between output current density and stimuli such as pressure, velocity, water absorption, and ion concentration. Demonstrating practical utility, the generated energy powers devices like a commercial calculator. This technology advances mechanical energy harvesting and multiple sensing, reducing dependence on external power and enabling transformative IoT applications.

Performance study of GaN-based betavoltaic nuclear batteries with 3D interfaces

This study presents a design of a 3D interface simulation model featuring an inverted pyramid structure. Our objective is to forecast the performance of GaN-based betavoltaic nuclear batteries with the PN junction 3D interface structures comparing a practical machining process. Initially, we computed the electron-hole pairs (EHPs) generation rate in GaN materials irradiated by both 63Ni and 147Pm sources using Geant4. Furthermore, we employed COMSOL Multiphysics, a finite element analysis software, to simulate the EHPs transport phenomena within the battery and investigate the influence of structural parameters on the output performance. Despite maintaining thicknesses of the P- and N-regions and consistent doping concentrations (Hp-GaN, Hn-GaN, Na, and Nd) as constants, the simulation results revealed notable disparities in the short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum output power density (Pmax) among batteries irradiated with various radioactive sources. Subsequently, we investigated the output performance of the nuclear battery by altering parameters such as the number of inverted pyramid structures, junction depth, and type of radioactive source. Our investigation revealed that selecting 63Ni as the radioactive source, with Na at 1017 cm−3, Nd at 1014 cm−3, a junction depth of 0.1 μm, and inverted pyramid structures of 25, resulted in the following battery performance parameters: a short-circuit current density (Jsc) of 0.648 μA/cm2, an open-circuit voltage (Voc) of 2.3481 V, and a maximum output power density (Pmax) of 1.2949 μW/cm2. Substituting the radioactive source with 147Pm, the average short-circuit current density, Jsc, increased to 56.865 μA/cm2, and the maximum output power density, Pmax, increased to 94.975 μW/cm2, It's a significant enhancement in output performance.

Multistate Ferroelectric Diodes with High Electroresistance Based on van der Waals Heterostructures.

Some van der Waals (vdW) materials exhibit ferroelectricity, making them promising for novel nonvolatile memories (NVMs) such as ferroelectric diodes (FeDs). CuInP2S6 (CIPS) is a well-known vdW ferroelectric that has been integrated with graphene for memory devices. Here we demonstrate FeDs with self-rectifying, hysteretic current-voltage characteristics based on vertical heterostructures of 10 nm thick CIPS and graphene. By using vdW indium-cobalt top electrodes and graphene bottom electrodes, we achieve a high electroresistance (on- and off-state resistance ratios) of ∼106, an on-state rectification ratio of 2500 for read/write voltages of 2 V/0.5 V, and a maximum output current density of 100 A/cm2. These metrics compare favorably with state-of-the-art FeDs. Piezoresponse force microscopy measurements show that stabilization of intermediate net polarization states in CIPS leads to stable multibit data retention at room temperature. The combination of two-terminal design, multibit memory, and low-power operation in CIPS-based FeDs is potentially interesting for compute-in-memory and neuromorphic computing applications.

Phase transformation enabled textile triboelectric nanogenerators for wearable energy harvesting and personal thermoregulation

The practical applications of environmentally friendly wearable textile triboelectric nanogenerators (t-TENGs) are constrained by inadequate heat dissipation, moisture permeability, and outdoor durability, particularly in humid and high-temperature environments. This study introduces a novel passive cooling strategy by integrating super-hydrophilic titanium dioxide solvent-free TiO2 nanofluids (TiO2 nfs) into cellulose acetate (CA) fibrous membranes (TiO2 nfs@CA) to achieve human comfort and efficient energy harvesting. Interestingly, the phase transformation of TiO2 nfs around boy temperature range (32-38 °C) effectively regulates the surface temperature of TiO2 nfs@CA fibrous membranes. In comparison with pristine CA fabric, TiO2 nfs@CA textile demonstrates exceptional solar reflectance (93.43%), high infrared emissivity (85%), excellent water vapor transport rate (12.6gm-2 h-1), and a significant cooling effect of 4-8 ℃ for both human skin and indoor environments. TiO2 nfs significantly enhances their ultraviolet resistance as well as mechanical properties and dielectric properties while improving triboelectric output performance with output voltage (66V), current (2.7 μA), and power density (82mWm-2). And TiO2 nfs@CA t-TENGs exhibit superior multifunctionality in terms of energy harvesting capabilities along with pressure sensing abilities for real-time movement monitoring including foot movements assessment as well as recovery evaluation for human body health maintenance purposes. Overall, TiO2 nfs@CA t-TENGs with the skin-friendly, dyeable, and recyclable properties provides a novel approach towards comfortable self-powered wearable devices that enable practical foot movement prediction alongside health monitoring.

Polymer-metal film induced ultrahigh output TVNG and self-powered intelligent sensor system assisted by EEMD

Tribovoltaic nanogenerators (TVNGs) based on tribovoltaic effect can output DC current directly, and has the advantages of high output current density and low internal resistance. While TVNGs have been restricted by its low output voltage and power. Herein, we have developed a metal-polymer film with a micro-uneven structure on the surface, much higher corrosion resistance and wear resistance than metal. On this basis, a centimeter-level sliding structure metal-EP/GaN-TVNG has been fabricated, which shows a high and stable long-term DC electrical output (a maximized power output of 4.19 W/m2 when matched with a 0.07 MΩ resistor, a stable output current of 2.25 A/m2 and a peak Voc of 27 V). Further, a TVNG vehicle travelling intelligent sensor and system which can integrate electrical signals collected by TVNG into digital signal processing algorithms and then feed backing to the driving system, has been designed and manufactured. As an effective method for deep analysis of signals, Ensemble Empirical Mode Decomposition (EEMD) has been used for the first time for deep processing of nanogenerator signals in this work. This work provides a new model of further development of high output TVNG and a new deep signal processing methods of TVNG/TENG signal.

Heterointerface of nickel-ferric hydroxide / cobalt-phosphide-boride boosting hydrazine-assisted water electrolysis

Sustainable H2 production based on hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) has attracted wide attention due to minimal energy consumption compared to overall water electrolysis. The present study focuses on the design and construction of heterostructured CoPB@NiFe–OH applied as efficient bifunctional catalysts to sustainable produce hydrogen and remove hydrazine in alkaline media. Impressively, CoPB@NiFe–OH heterointerface exhibits an HzOR potential of −135 mV at the current density of 10 mA cm−2 when the P to B atom ratio was 0.2, simultaneously an HER potential of −32 mV toward HER when the atom ratio of P and B was 0.5. Thus, hydrogen production without an outer voltage accompanied by a small current density output of 25 mA cm−2 is achieved, surpassing most reported catalysts. In addition, DFT calculations demonstrate the Co sites in CoPB upgrades H∗ adsorption, while the Ni sites in NiFe–OH optimizes the adsorption energy of N2H4∗ due to electron transfer from CoPB to NiFe–OH at the heterointerface, ultimately leading to exceptional wonderful performance in hydrazine-assistant water electrolysis via HER coupled with HzOR.

Improved DC and RF Characteristics of GaN-Based Double-Channel HEMTs by Ultra-Thin AlN Back Barrier Layer.

In order to improve the off-state and breakdown characteristics of double-channel GaN HEMTs, an ultra-thin barrier layer was chosen as the second barrier layer. The strongly polarized and ultra-thin AlN sub-barrier and the InAlN sub-barrier are great candidates. In this article, the two epitaxial structures, AlGaN/GaN/AlN/GaN (sub-AlN) HEMTs and AlGaN/GaN/InAlN/GaN (sub-InAlN) HEMTs, were compared to select a more suitable sub-barrier layer. Through TEM images of the InAlN barrier layer, the segregation of In components can be seen, which decreases the mobility of the second channel. Thus, the sub-AlN HEMTs have a higher output current density and transconductance than those of the sub-InAlN HEMTs. Because the high-quality AlN barrier layer shields the gate leakage current, a 294 V breakdown voltage was achieved by the sub-AlN HEMTs, which is higher than the 121 V of the sub-InAlN HEMTs. The current gain cut-off frequency (fT) and maximum oscillation frequency (fmax) of the sub-AlN HEMTs are higher than that of the sub-InAlN HEMTs from low to high bias voltage. The power-added efficiency (PAE) and output power density (Pout) of the sub-AlN HEMTs are 57% and 11.3 W/mm at 3.6 GHz and 50 V of drain voltage (Vd), respectively. For the sub-InAlN HEMTs, the PAE and Pout are 41.4% and 8.69 W/mm, because of the worse drain lag ratio. Thus, the Pout of the sub-AlN HEMTs is higher than that of the sub-InAlN HEMTs.

Tungsten-liquid triboelectric nanogenerator for water-flowing energy harvesting with low-resistance and high-DC density

In the new energy era, triboelectric nanogenerator (TENG) effectively converts weak water energy into electricity to drive sensors and electronic components, which has a very broad research prospect. However, the functional materials of TENG are usually insulating, resulting in low-current and high-resistance problems. Guided by Wang's electrical double layer model, we demonstrate that tungsten presents excellent electricity generation performance in flowing water due to its unique defect structure as evidenced by comparing the electricity generation of tungsten, tantalum, titanium, and copper, and testing their electrochemical impedance spectroscopy and X-ray diffraction characteristics. Hence, the study proposes a novel tungsten-liquid TENG for water-flowing energy harvesting, which has outstanding advantages of high DC density, low internal resistance, simple structure, and no complex electrical power required. A tungsten-liquid TENG continuously outputs 3∼20μA in 0.1–2.0M NaCl liquids at a flow rate of 400 mL/min, with output current densities up to 230 mA/m2 and internal resistances down to 6.4–67 kΩ. Ten-tungsten-liquid TENG outputs nearly 40μA, and multiple tungsten electrodes in parallel can effectively enhance the current. Notably, the study is not only beneficial for capturing the current energy in oceans with high-ionic concentrations, but also broadens the research ideas of TENG for promoting the selection of novel functional materials.

Utilization of the easy electron-losing capacity of dog fur waste for green energy devices and self-powered smart pet care systems

The present global energy shortage and climate crisis can be addressed by embracing recycling, reuse, and recovery; for example, this can be achieved by methodically utilizing the problematic wastes for energy harvesting. This research describes a novel approach for recovery and reutilization of waste material by incorporating dog fur waste into a triboelectric energy harvester; this was accomplished via a simple, inexpensive, and eco-friendly chemical processing to turn this problematic waste into a high-performance tribolayer. Due to the complications of operating practical devices with dog fur in its natural form, the dog fur waste was transformed for the first time into a uniform thin-film-based high-performance positive tribolayer. The optimization of the fabrication of the dog fur film featured hexagonal pyramid nanostructures, and a novel tribopair was selected and consisted of the dog fur-based film and a Teflon film; these films have very large differences in electron affinities. Based on this optimization and selection, we achieved an outstanding output voltage, current, and power density of 2021.46 V, 109.84 μA and 24,669.957 μWcm−2, respectively, along with appreciable mechanical stability during continuous operation up to 10,000 cycles. Our research demonstrates the potential for integration of green electronics and self-powered human-pet interaction systems while providing a sustainable approach to a circular bioeconomy.

Hybrid dual-mode high-output triboelectric nanogenerator for achieving alternating current/direct current collaborative output

The large-scale practical application of triboelectric nanogenerators (TENGs) mainly depends on the limitations of output performance. On the basis of previous theory, this paper proposes a comprehensive strategy on the coupling of triboelectrification, corona discharge, volume effect, and space volume utilization of charge capture to enhance TENGs’ output. Thereby, a hybrid dual-mode high-output TENG (HDH-TENG) is proposed to efficiently harvest natural mechanical energy through a rotation-driven sliding-TENG (RS-TENG) and a magnetic-driven contact-separation TENG (MC-TENG). The simplified sliding-TENG with the combination of PU foam and vertical-radial electrodes achieves AC/DC collaborative output with charge density of 173.3 and 175.2 µC m−2, respectively. The simplified contact-separation TENG with the PU foam achieves AC output with charge density of 108.8 µC m−2. Furthermore, the integrated RS-TENG and MC-TENG achieve efficient collaborative output of DC with power density of 6.4 W m−2 Hz−1 and AC with power density of 128.6 mW m−2 Hz−1 through persistent directional sliding and contact separation, respectively, where a record-high constant current density output reached 1.9 mA m−2 Hz−1. The HDH-TENG can drive 6575 LEDs and 12 incandescent lamps, and continuously and stably power 52 hygrothermographs. This work further provides a new strategy for charge density enhancement of TENGs.

Investigation of an Ethanol Electroreforming Cell Based on a Pt1Ru1/C Catalyst at the Anode

The production of H2 from renewable sources represents a crucial challenge for the planet’s future to achieve net zero emissions and store renewable energy. A possible alternative to water electrolysis (WE), which requires high potential (E > 1.48 V) to trigger the oxygen evolution reaction (OER), would be alcohol electrochemical reforming (ER), which implies the oxidation of short organic molecules such as methanol or ethanol. In ER, energy must be supplied to the system, but from a thermodynamic point of view, the energy request for the methanol or ethanol oxidation reaction is much lower than that of the OER. To study this process, an in-house 50 wt.% Pt1Ru1/C anodic catalyst was easily synthesized according to the Pt sulphite complex route and the impregnation of a carbon support (Ketjenblack, KB) and a Ru precursor. X-ray diffraction (XRD), X-ray fluorescence (XRF) spectroscopy, and Transmission Electron Microscopy (TEM) were used to characterize the structure, composition, and morphology of the catalyst. It appears that two distinct crystallographic phases of the Pt and Ru nanoparticles were encountered after the synthesis conducted by Ru impregnation. For the electrochemical measurements, ethanol electrooxidation (2 M CH3CH2OH) was studied first in a half cell with a rotating disc electrode (RDE) configuration under acid conditions and then in a direct ethanol electroreforming (or electrolysis) cell, equipped with a proton exchange membrane (PEM) as the electrolyte. The output current density was 0.93 A cm−2 at 1 V and 90 °C in 2 M ethanol. The remarkable current densities obtained in the alcohol electrolyzer at a low voltage are better than the actual state of the art for PEM ethanol ER.

Performance-enhanced tribovoltaic nanogenerator by regulating carrier transportation with an asymmetric heterostructure

The tribovoltaic nanogenerator (TVNG) is emerging as a promising circuit-integrative energy harvester, with notable advantages like direct current output and large current density. Nevertheless, the research on optimizing charge excitation and carrier transportation remains deficient. In this work, we report an alternative approach for practically promoting the output performance of silicon (Si)-based TVNG. A well-designed asymmetric heterostructure is achieved by inserting an appropriate interlayer between the friction layer and the bottom electrode. Carrier extraction efficiency has been promoted effectively, while carrier recombination has been restrained owing to the built-in electric field excited by p-Si/ZnO heterojunction. The coupling mechanism of the built-in electric field and the interfacial electric field has been revealed explicitly with a comprehensive theoretical model, which is based on the capacitance feature of the PN junction. The designed multilayer TVNG (MTVNG) has shown 20 times higher output compared to normal Si-based TVNGs. Apart from presenting fundamental insights into the tribovoltaic effect, we have developed a dual-mode analysis method for vibration monitoring. This work expands the path to improve TVNG output through multi-electric field coupling and provides new inspiration for miniaturized vibration sensors in real-time deployments.

Comparison of lifetime performance of PEMFC stacks with two cooling strategies under different humidity

While reducing the size and Pt loading can achieve a lower proton exchange membrane fuel cell (PEMFC) stack cost, it is also very important to focus on the performance changes of the PEMFC stack during the long-term operation. A 3D PtCo catalysts long-term performance model is established in this study, and PEMFC stacks with one cooling unit per cell (1-cell stack) and three cells (3-cell stack) are employed as the computational domains, respectively. The effective area of each cell is 50 cm2, and the changes in current density as well as effective catalytic area of PEMFC stacks with two cooling strategies before and after long-term operation under different humidity conditions are investigated at low Pt loadings. The results show that there are large differences in the output voltage and current density distributions between the three cells due to the poor membrane hydration affected by the non-uniform temperature distribution, although the 3-cell stack can significantly reduce the size. Localized catalyst degradation in both 3-cell and 1-cell stacks is closely related to the geometry of the cathodic flow field, and non-uniform catalyst degradation is found to increase the activation and mass transfer losses and change the distribution of current density within the membrane. In addition, the 3-cell stack is found to perform even better in terms of durability, especially under high humidity conditions, which provides a potential solution to improve the durability of PEMFC stacks operating in harsh conditions.

Theoretical Investigation of Proton Exchange Membrane Fuel Cells Oriented to Automotive Applications

<p>Because of their efficiency and low environmental effect, proton exchange membrane fuel cells, or PEMFCs, are discussed in this abstract as a viable renewable energy source. The paper investigates PEMFCs theoretically, delving into their electrochemical mechanisms and developing a MATLAB simulation model to verify theoretical understanding. Performance parameters such as cell voltage, current density, and power output are assessed in the simulation under various scenarios. The study reveals a number of variables, including temperature, pressure, hydrogen concentration, water quality, and more, that impact PEMFC effectiveness. The best operating conditions for greatest efficiency are found by adjusting these variables and seeing how they affect power production. Furthermore, the study evaluates PEMFC viability for electric cars and comprehends the cell's response to mechanical strain. To sum up, this study uses MATLAB simulations and theoretical analysis to comprehend PEMFC behavior. The results are validated by experiments, which adds credibility to the model. The results support the advancement of PEMFC technology and the creation of sustainable energy sources.</p>

Thermal-flow-force-electrical coupling characteristics of microchannel cooling systems in high heat flux chips

To address the challenges faced by designers of multi-field coupled cooling systems for high heat flux chips, this paper proposes a “near-source” microchannel cooling strategy and establishes a thermal–flow-force electrically coupled model for chips. The effects of chip Joule heat and cooling water flow rate on the cooling performance with respect to multi-field coupling effects were studied. The impact of multi-field coupling effects was revealed, and a method for enhancing microchannel cooling performance in light of multi-field coupling effects is proposed. The results indicated that considering multi-field coupling effects in the microchannel cooling process leads to a deterioration in the thermal performance of chips, accompanied by a significant increase in electrical fluctuations and thermal deformation amplitude. Compared to chips upstream of the cooling water, chips downstream subjected to thermal cascade effects were more sensitive to multi-field coupling effects. Moreover, the temperature variance index, output current, and strain energy density of high heat flux chips were positively correlated with Joule heat but inversely proportional to the Reynolds number of the cooling water for cases in respect of multi-field coupling effects. Additionally, serpentine microchannels maximized the operational performance of high heat flux chips by reducing temperature of chip by up to 55.1%, decreasing strain energy density by 96.7%, and increasing input potential by 120%.

A high performance triboelectric nanogenerator using assembled sugar naphthalimides for self-powered electronics and sensors

A new class of N-glycosyl naphthalimide ricinoleate (NGNR) amphiphiles were generated using environmentally friendly reaction conditions in good yields. To investigate the potential applications of NGNR amphiphiles within the realm of supramolecular materials, molecular self-assembly experiments were conducted extensively across a diverse range of solvents and oils and observed the gel formation. Molecular-level interactions and assembly patterns were investigated by employing FTIR, SAXRD, UV–vis, and fluorescence spectroscopy, and a plausible assembly mechanism was proposed. The morphology of the supramolecular architecture was identified by scanning electron microscopy. Additionally, rheological studies provided insight into these soft materials' strength and processability. Further, in the process of fabricating a triboelectric nanogenerator (TENG) device, silicone rubber serves as an electron acceptor and assembled NGNR serves as an electron donor. The developed TENG demonstrated a significant improvement in performance over TENG made with amorphous NGNR, with output voltage, current, and power density of 410 V, 100 µA, and 5.1 W/m2, respectively, highlighting the importance of the assembly process. Furthermore, TENG is used to continuously power up small electronic device (calculator), which is useful in building self-powered electronic devices. Lastly, due to its high sensitivity and stability, the TENG was used to detect the humidity of the environment in the food processing, textile, and agriculture sectors. The change in TENG response is notably significant up to 70 % relative humidity (RH). This work showcases the development of self-powered humidity sensors.

Improved surface activity of lanthanum ferrite perovskite oxide through controlled Pt-doping for solid oxide cell (SOC) electrodes

The development of multi-functional and highly mixed ionic-electronic conductive perovskite oxide-based electrodes is becoming an established trend for designing and developing SOFC/SOEC reversible cells. Ideally, the same material can be employed at both electrodes provided that structural stability, high conductivity and catalytic activity are preserved in different operational atmospheres. Here, controlled Fe substitution with a small extent (0.5 mol%) of platinum at the B-site of a lanthanum strontium ferrite is proposed as an effective method to enhance the original oxide properties as both air and fuel electrode for solid oxide cells. The effects of low Pt-doping on La0.6Sr0.4FeO3-δ structure, morphology and electrocatalytic activity are investigated and discussed. La0.6Sr0.4Fe0.995Pt0.005O3-δ (05P-LSF) is first tested as air electrode, displaying lower area specific resistance as compared to the Pt-free perovskite. 05P-LSF structural stability and conductivity are assessed in 100 % CO2 and 50 % CO2–50 % CO environments. Symmetric devices are then tested as SOECs in 100 % CO2, obtaining a current density output of 1.08 A/cm2 at 1.5 V. Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times analysis (DRT) are used to provide insights on the electrode operation. Pt nanoparticle exsolution at the fuel electrode is induced by voltage application. The device stability under applied voltage is assessed for over 120 h. SOFC/SOEC characterization in a 50 % CO2/50 % CO mixture at 850 °C is also provided, obtaining a maximum power density of 270 mW/cm2 in SOFC mode, and a current density of 0.91 A/cm2 at 1.5 V in SOEC mode.

The effect of curved membrane electrode assemblies on performances of parallel and interdigitated flow field PEMFCs with wavelike gas channels

The effect of curved membrane electrode assemblies (MEAs) on performances of parallel and interdigitated flow field PEMFCs with wavelike gas channels (GCs) are for the first time investigated at various curved MEA deformation levels, where the curved MEA is triggered by the pressure difference between anodes and cathodes. The results show that on the cathode side of parallel flow field PEMFCs with wavelike GCs, the oxygen consumption and liquid water generation are small with the increased MEA deformation level at the high operation voltage being larger than 0.8 V, leading to the constant cell performance, that is, leading to the constant output current density. However, the current density is first increased and then decreased with the increased MEA deformation level at the low operation voltage being less than 0.8 V. Because at the low operation voltage, the oxygen consumption and liquid water generation are significantly increased and affected by the increased MEA deformation level. When the MEA deformation level is increased at the high operation voltage being larger than 0.8 V, the current density of interdigitated flow PEMFCs with wavelike GCs is also constant because of small oxygen consumptions and liquid water generations. However the oxygen consumption and liquid water generation are large enough and depend on the oxygen transport and liquid water removal at the low operation voltage being less than 0.8 V. At the low voltage, the oxygen transport and liquid water removal are modified by the increased MEA deformation level. Consequently the current density is first decreased and then increased at the low operation voltage.