Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in...Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in the membrane electrode assembly (MEA) of each cell, in which the moisture of the cathode exhaust gas could transfer through the membrane to humidify anode or cathode dry gas. With a simple model, the relative humidity (RH) of the dry air exhaust from a membrane humidifier with 100% RH stream as a counter flow is calculated to be 60.0%, which is very close to the experimental result (62.2%). Fuel cell performances with hydrogen humidifying, air humidifying and no humidifying are compared at 50, 60 and 70°C and the results indicate that humidifying is necessary and the novel design with humidifying zone in MEA is effective to humidify dry reactants. The hydrogen humidifying shows better performance in short term, while water recovered is limited and the stability is not as good as air humidifying. It is recommended that both air and hydrogen should be humidified with proper design of the humidifying zones in MEA and plates.展开更多
In this study, the transfer method is employed to add hydrophilic SiO2 nanopowders to a Pt/C catalyst ink to form an anode catalyst layer on a proton exchange membrane (PEM). The SiO2-layered membrane electrode assemb...In this study, the transfer method is employed to add hydrophilic SiO2 nanopowders to a Pt/C catalyst ink to form an anode catalyst layer on a proton exchange membrane (PEM). The SiO2-layered membrane electrode assembly improves the performance of the PEM under low- or zero-humidification conditions. When the PEM fuel cell (PEMFC) undergoes electrochemical reaction, the moisture content of the PEM exhibits a substantial influence on the transmission of protons. To ensure the moisture content remains high, an external humidifier is typically employed to humidify the majority of PEMFCs. However, self-humidifying PEMFCs could utilize the water produced by the fuel cell reaction, thereby eliminating the need for an external humidifier. In this study, various SiO2 loadings were added to an anode catalyst layer, and the cell temperature and gas humidification conditions were adjusted to determine the influence of the SiO2 loadings on the fuel cell performance. The results show that adding SiO2 is preferable to not adding SiO2 when the fuel cell temperature is 50°C.展开更多
The development of multi-physics-resolved digital twins of proton exchange membrane fuel cells(PEMFCs)is sig-nificant for the advancement of this technology.Here,to solve this scientific issue,a surrogate modelling me...The development of multi-physics-resolved digital twins of proton exchange membrane fuel cells(PEMFCs)is sig-nificant for the advancement of this technology.Here,to solve this scientific issue,a surrogate modelling method that combines a state-of-the-art three-dimensional PEMFC physical model and data-driven model is proposed.The surrogate modelling prediction results demonstrate that the test-set relative root mean square errors(rRMSEs)of the multi-physics fields range from 3.88%to 24.80%and can mirror the multi-physics field distribution charac-teristics well.In summary,for multi-physics field prediction,the data-driven surrogate model has a comparable accuracy to the comprehensive 3D physical model;however,it considerably reduces the cost of computation and time and achieves the efficient multi-physics-resolved digital-twin.Two model-based designs based on the as-developed digital twin framework,i.e.the PEMFC healthy operation envelope and the PEMFC state map,are demonstrated.This study highlights the potential of combining data-driven approaches and comprehensive physical models to develop the digital twin of complex systems,such as PEMFCs.展开更多
Structural optimization of ionomers is an effective strategy for achieving high-performance proton ex-change membranes(PEMs)under low relative humidity(RH)conditions.In this study,sulfonimide group and trifluoromethan...Structural optimization of ionomers is an effective strategy for achieving high-performance proton ex-change membranes(PEMs)under low relative humidity(RH)conditions.In this study,sulfonimide group and trifluoromethanesulfonate acid(TFSA)ionic liquids were introduced to the perfluorosulfonic acid(PFSA)side chain,resulting in polymer membranes with varying chain lengths(i.e.,PFC_(2)-TF-SI,PFC_(4)-TF-SI,and PFC_(5)-TF-SI).This dual proton-conducting structure extended the length of the hydrophilic side chain and enhanced the hydrophobic-hydrophilic phase separation,aiding in the formation of proton transport channels.Notably,the proton conductivity of PFC_(5)-TF-SI and PFC_(2)-TF-SI membranes reached 7.1 and 10.6 mS/cm at 30%RH and 80℃,respectively,which were approximately 29.1%and 92.7%higher than that of the pristine PFC_(5)-SA membrane(5.5 mS/cm).Furthermore,the maximum power density of the PFC_(5)-TF-SI and PFC_(2)-TF-SI membranes from the built single fuel cell achieved 649 and 763 mW/cm^(2) at 30%RH and 80℃,respectively,which were higher than that of the pristine PFC_(5)-SA membrane(567 mW/cm^(2))by about 14.5%and 34.6%,respectively.Thus,this study provides a strategy for PEM design under low RH conditions.展开更多
The effective cathode flow field design can realize the internal water balance and higher current density output of proton exchange membrane fuel cells(PEMFC).Therefore,a segmented water management flow field is propo...The effective cathode flow field design can realize the internal water balance and higher current density output of proton exchange membrane fuel cells(PEMFC).Therefore,a segmented water management flow field is proposed in this study,i.e.a half separated-half coupled cathode(HSHC)flow field which has two inlets but just one outlet.A 3D numerical PEMFC model is applied to study the effect of the HSHC flow field on PEMFC performance and its operating strategy in terms of operating conditions.The study results are shown as follows:Compared with the two conventional cathode flow fields,the HSHC flow field improves the water balance along the channel and increases the current density by 17.1%at a cathode stoichiometry of 3.25.It is because the HSHC flow field can overcome the water loss at channels upstream and the water accumulation at channels downstream.The draw water phenomenon(DWP)in the HSHC flow field is observed,which is mainly affected by the water vapor pressure of channel.Based on the DWP,cooling channel inlet flow rates can be used to adjust water balance,but severe water loss should be avoided.In addition,the inlet temperature control in HSHC flow field should be that cell temperature>cathode channel inlet temperature>cooling channel inlet temperature>ambient temperatures for better water balance.展开更多
A novel nano-porous material SiO2-gel was prepared. After being purified by H2O2, then protonized by H2SO4 and desiccated in vacuum, the SiO2-gel, mixed with Nafion solution, was coated between an electrode and a soli...A novel nano-porous material SiO2-gel was prepared. After being purified by H2O2, then protonized by H2SO4 and desiccated in vacuum, the SiO2-gel, mixed with Nafion solution, was coated between an electrode and a solid electrolyte, which made a new type of self-humidifying membrane electrode assembly. The SiO2 powder was characterized by FTIR, BET and XRD. The surface of the electrodes was characterized by SEM and EDS. The performances of the self-humidifying membrane electrodes were analyzed by polarization discharge and AC impedance under the operation modes of external humidification and self-humidification respectively. Experimental-results indicated that the SiO2 powder held super-hydrophilicity, and the layer of SiO2 and Nafion polymer between electrode and solid electrolyte expanded three-dimension electrochemistry reac-tion area, maintained stability of catalyst layer and enhanced back-diffusion of water from cathode to anode, so the PEM Fuel cell can generate electricity at self-humidification mode. The power density of single PEM fuel cell reached 1.5 W/cm2 under 0.2 Mpa, 70°C and dry hydrogen and oxygen.展开更多
A novel method for the preparation of a self-humidifying MEA used for PEMFC and the optimum conditions for the fabrication are presented. Different from the method involved dispersion of Pt particles through out the m...A novel method for the preparation of a self-humidifying MEA used for PEMFC and the optimum conditions for the fabrication are presented. Different from the method involved dispersion of Pt particles through out the membrane or between two thin membranes. The new type self-humidifying MEA gain self-humidifying operation by asymmetry electrode. The anode with 0.1 mg Pt/cm 2, has super-hydrophilicity by coating the hydrophilic colloid, while the cathode with 0.4 mg Pt/cm 2, has a strong hydrophobic nature by doping PTFE. When the current density is less than 2.3 A/cm 2, the discharge performance of the humidifying gases little excel the self-humidifying operation, but more than 2.3 A/cm 2, the self-humidifying operation do better than humidifying gases operation, and the most power density reaches over 1.5 W/cm 2. Inner resistance of electrochemistry reaction and transportation are studied by the AC impedance method, and validate that the self-humidifying MEA can give a good three-dimension reaction area with dry hydrogen and dry oxygen.展开更多
基金Supported by the National High Technology Research and Development Program of China (2008AA05Z104)
文摘Water management is of great importance to maintain performance and durability of proton exchange membrane fuel cells. This paper presents a novel proton exchange membrane (PEM) fuel cell with a humidification zone in the membrane electrode assembly (MEA) of each cell, in which the moisture of the cathode exhaust gas could transfer through the membrane to humidify anode or cathode dry gas. With a simple model, the relative humidity (RH) of the dry air exhaust from a membrane humidifier with 100% RH stream as a counter flow is calculated to be 60.0%, which is very close to the experimental result (62.2%). Fuel cell performances with hydrogen humidifying, air humidifying and no humidifying are compared at 50, 60 and 70°C and the results indicate that humidifying is necessary and the novel design with humidifying zone in MEA is effective to humidify dry reactants. The hydrogen humidifying shows better performance in short term, while water recovered is limited and the stability is not as good as air humidifying. It is recommended that both air and hydrogen should be humidified with proper design of the humidifying zones in MEA and plates.
文摘In this study, the transfer method is employed to add hydrophilic SiO2 nanopowders to a Pt/C catalyst ink to form an anode catalyst layer on a proton exchange membrane (PEM). The SiO2-layered membrane electrode assembly improves the performance of the PEM under low- or zero-humidification conditions. When the PEM fuel cell (PEMFC) undergoes electrochemical reaction, the moisture content of the PEM exhibits a substantial influence on the transmission of protons. To ensure the moisture content remains high, an external humidifier is typically employed to humidify the majority of PEMFCs. However, self-humidifying PEMFCs could utilize the water produced by the fuel cell reaction, thereby eliminating the need for an external humidifier. In this study, various SiO2 loadings were added to an anode catalyst layer, and the cell temperature and gas humidification conditions were adjusted to determine the influence of the SiO2 loadings on the fuel cell performance. The results show that adding SiO2 is preferable to not adding SiO2 when the fuel cell temperature is 50°C.
基金This research is supported by the China-UK International Coopera-tion and Exchange Project(Newton Advanced Fellowship)jointly sup-ported by the National Natural Science Foundation of China(grant No.51861130359)the UK Royal Society(grant No.NAF\R1\180146)the Natural Science Foundation of Tianjin(China)for Distinguished Young Scholars(Grant No.18JCJQJC46700).
文摘The development of multi-physics-resolved digital twins of proton exchange membrane fuel cells(PEMFCs)is sig-nificant for the advancement of this technology.Here,to solve this scientific issue,a surrogate modelling method that combines a state-of-the-art three-dimensional PEMFC physical model and data-driven model is proposed.The surrogate modelling prediction results demonstrate that the test-set relative root mean square errors(rRMSEs)of the multi-physics fields range from 3.88%to 24.80%and can mirror the multi-physics field distribution charac-teristics well.In summary,for multi-physics field prediction,the data-driven surrogate model has a comparable accuracy to the comprehensive 3D physical model;however,it considerably reduces the cost of computation and time and achieves the efficient multi-physics-resolved digital-twin.Two model-based designs based on the as-developed digital twin framework,i.e.the PEMFC healthy operation envelope and the PEMFC state map,are demonstrated.This study highlights the potential of combining data-driven approaches and comprehensive physical models to develop the digital twin of complex systems,such as PEMFCs.
基金This work was financially supported by the National Key Re-search and Development Program of China(No.2022YFB4003500)the National Natural Science Foundation of China(No.T2241003)+2 种基金the Key R&D Project of Hubei Province,China(No.2021AAA006)the National Natural Science Foundation of China(No.52202009)The researchers would like to acknowledge Deanship of Scientific Research,Taif University for funding this work.HA is thankful to the Deanship of Scientific Research at Najran University for funding this work,under the Research Groups Funding program grant code(NU/RG/SERC/12/10).
文摘Structural optimization of ionomers is an effective strategy for achieving high-performance proton ex-change membranes(PEMs)under low relative humidity(RH)conditions.In this study,sulfonimide group and trifluoromethanesulfonate acid(TFSA)ionic liquids were introduced to the perfluorosulfonic acid(PFSA)side chain,resulting in polymer membranes with varying chain lengths(i.e.,PFC_(2)-TF-SI,PFC_(4)-TF-SI,and PFC_(5)-TF-SI).This dual proton-conducting structure extended the length of the hydrophilic side chain and enhanced the hydrophobic-hydrophilic phase separation,aiding in the formation of proton transport channels.Notably,the proton conductivity of PFC_(5)-TF-SI and PFC_(2)-TF-SI membranes reached 7.1 and 10.6 mS/cm at 30%RH and 80℃,respectively,which were approximately 29.1%and 92.7%higher than that of the pristine PFC_(5)-SA membrane(5.5 mS/cm).Furthermore,the maximum power density of the PFC_(5)-TF-SI and PFC_(2)-TF-SI membranes from the built single fuel cell achieved 649 and 763 mW/cm^(2) at 30%RH and 80℃,respectively,which were higher than that of the pristine PFC_(5)-SA membrane(567 mW/cm^(2))by about 14.5%and 34.6%,respectively.Thus,this study provides a strategy for PEM design under low RH conditions.
基金the financial support for this research from the National Natural Science Foundation of China(52176063)the International Science and Technology projects of Huangpu District of Guangzhou City(2020GH08)the Guangzhou Science and Technology Plan Project(201907010036)。
文摘The effective cathode flow field design can realize the internal water balance and higher current density output of proton exchange membrane fuel cells(PEMFC).Therefore,a segmented water management flow field is proposed in this study,i.e.a half separated-half coupled cathode(HSHC)flow field which has two inlets but just one outlet.A 3D numerical PEMFC model is applied to study the effect of the HSHC flow field on PEMFC performance and its operating strategy in terms of operating conditions.The study results are shown as follows:Compared with the two conventional cathode flow fields,the HSHC flow field improves the water balance along the channel and increases the current density by 17.1%at a cathode stoichiometry of 3.25.It is because the HSHC flow field can overcome the water loss at channels upstream and the water accumulation at channels downstream.The draw water phenomenon(DWP)in the HSHC flow field is observed,which is mainly affected by the water vapor pressure of channel.Based on the DWP,cooling channel inlet flow rates can be used to adjust water balance,but severe water loss should be avoided.In addition,the inlet temperature control in HSHC flow field should be that cell temperature>cathode channel inlet temperature>cooling channel inlet temperature>ambient temperatures for better water balance.
基金This work was supported by the "973" Project of Ministry of ScienceTechnology in China.
文摘A novel nano-porous material SiO2-gel was prepared. After being purified by H2O2, then protonized by H2SO4 and desiccated in vacuum, the SiO2-gel, mixed with Nafion solution, was coated between an electrode and a solid electrolyte, which made a new type of self-humidifying membrane electrode assembly. The SiO2 powder was characterized by FTIR, BET and XRD. The surface of the electrodes was characterized by SEM and EDS. The performances of the self-humidifying membrane electrodes were analyzed by polarization discharge and AC impedance under the operation modes of external humidification and self-humidification respectively. Experimental-results indicated that the SiO2 powder held super-hydrophilicity, and the layer of SiO2 and Nafion polymer between electrode and solid electrolyte expanded three-dimension electrochemistry reac-tion area, maintained stability of catalyst layer and enhanced back-diffusion of water from cathode to anode, so the PEM Fuel cell can generate electricity at self-humidification mode. The power density of single PEM fuel cell reached 1.5 W/cm2 under 0.2 Mpa, 70°C and dry hydrogen and oxygen.
文摘A novel method for the preparation of a self-humidifying MEA used for PEMFC and the optimum conditions for the fabrication are presented. Different from the method involved dispersion of Pt particles through out the membrane or between two thin membranes. The new type self-humidifying MEA gain self-humidifying operation by asymmetry electrode. The anode with 0.1 mg Pt/cm 2, has super-hydrophilicity by coating the hydrophilic colloid, while the cathode with 0.4 mg Pt/cm 2, has a strong hydrophobic nature by doping PTFE. When the current density is less than 2.3 A/cm 2, the discharge performance of the humidifying gases little excel the self-humidifying operation, but more than 2.3 A/cm 2, the self-humidifying operation do better than humidifying gases operation, and the most power density reaches over 1.5 W/cm 2. Inner resistance of electrochemistry reaction and transportation are studied by the AC impedance method, and validate that the self-humidifying MEA can give a good three-dimension reaction area with dry hydrogen and dry oxygen.
