Periodic Reporting for period 1 - ELECTRA (REdox fLow batteriEs powered by eCo-maTeRiAls)
Berichtszeitraum: 2022-03-01 bis 2024-02-29
Novel materials and developments for Energy Storage applications are the most active and successful research topics in Europe. Redox flow batteries (RFBs) are the very attractive option for the implementation of the intermittent renewable energy as they promise long lifespam in a design with independently energy/powers output. However, the bottleneck to realize this energy scenario is the lack of stable and inexpensive components, which substantially breaks the energy storage/power limits. Thus, we propose to investigate a family of earth-abundant and recyclable materials, based on transition metal oxyanions clusters (POMs). This appealing alternative provides fast multielectron transfer processes, offering excess of capacity in a reversible and stable fashion. Our research program involves the creation of electron-rich POMs structures based on W and Mo atoms in a low-cost synthesis process, suitable for large production. The outcomes of this work will include next generation of RFB with unprecedent energy and power values targeted, new understanding of mechanism in the interface, providing the guidance for exploiting new concept of energy storage in the future.
The main goals of the project are:
•Creating a stable family of POMs with fast and reversible multi-electron processes properties: Aiming to increase the functionality of the POMs endowing optimized electrochemical properties.
• To maximize the energy density and power values
• Interfaces characterization and validation of components:
The main goals of the project are:
•Creating a stable family of POMs with fast and reversible multi-electron processes properties: Aiming to increase the functionality of the POMs endowing optimized electrochemical properties.
• To maximize the energy density and power values
• Interfaces characterization and validation of components:
The main results are presented as follow:
1) Synthesis of new polyoxometalates (POMs) :ELECTRA project has been mostly focused on the following POMs: PV14; Fe4(PW9)2 and SiV3W9.
2) Evaluation of commertial POMs in flow cell:For that commercial POMs has been implemented in 0.5 M H2SO4 (typical electrolyte for those POMs allowing stability of the POM) SiMo12 / SiW12 and PMo12/OW12. Indeed, to maximize the success of the ELECTRA goals, substitution of W by more environmentally friendly atoms like Fe has been performed. Here, Fe4(PW9)2 can be an intriguing choice since a total of 8e- (4 e- from Fe and 4e- from W) can be involved in the redox process with the instability problems inherent in the structure. Under a performance perspective, PV14 and SiV3W9 show many benefits like easy to prepare in contrast to substituted POMs and, additionally, the synthesis yield is notable.
3) Evaluation of PV14; Fe4(PW9)2 and SiV3W9. In deep investigation has been carried out in order to implement the POMs in electrolytes using characterization techniques like FTIR and NMR. The stability of the POMs clusters is quite dependence of the pH. Thus, strong changes in the pH values could provoke a precipitation of the POMs and, in consequence, failure in the battery. ELECTRA project took a new approach with the implementation of the POM in to electrolyte using buffers instead of salts. In that approach, the H+ concentration changes can be mitigated for the action of the buffer. In this framework, it has been found that 1M acetate/acetic pH 3.7 for PV14 and pH 5 for Fe4(PW9)2 was the best one, provinding highly stability. For the case of SiV3W9 only the 3 atoms of V can operate under 1M acetate/acetic pH 5. Finally, the battery with PV14 and Fe4(PW9)2 has been demonstrated, achieving a capacity of 20 mAh. Particularly, the stability of the Fe4(PW9)2 is remarkable allowing the operation up to -1.2V (without the production of hydrogen evolution reaction) and more than 44 hours.
4) Implementation of bipolar electrochemistry into RFB for the first time, providing decrement of the resistance of the cell and allowing higher power densities as well as capacity . It is important to remar that the capacity obtained even surpasses the theoretical capacity of the electrolyte. This fact only can be explained by assuming that the potential induced in the BPE are enough to provide a contrary reaction of the driving electrodes, allowing the regeneration of the vanadium electrolyte.
5) Interfaces characterization and validation of components by employing new methodologies like Synchrotron x-ray absorption spectroscopy: i) Design of the cell specially for measuring in operando synchrotron radiation since it was measure for the first time in Alba facilities, ii) In operando measurements of Fe4(PW9)2..As a conclusion, the FePOM synthesised in ELECTRA project has been evaluated allowing insights of the stability and reversibility as well their structure.
in terms of exploitation and dissemination:The project results will be disseminated in scientific publications, which are under preparation. CF will first and corresponding author of both of them and will be published in Open Access, containing the EU funding.
In parallel, CF has been publishing 4 articles articles taking account her expertise in RFB in collaboration with her network. All publications are Open Access and contain the EU funding.
Conferences: DeCarbon International Conference 2023; EMRS 2022. In addtion it is planed :CF is going to the International Forum Flow Battery (Glasgow, 2024) where she has an accepted talk. In parallel, CF has an invited talk in the 75th Annual Meeting of the International Society of Electrochemistry" (2024, Montréal, Canada) within the symposium Electrochemistry - science and technology for a sustainable and better planet"
1) Synthesis of new polyoxometalates (POMs) :ELECTRA project has been mostly focused on the following POMs: PV14; Fe4(PW9)2 and SiV3W9.
2) Evaluation of commertial POMs in flow cell:For that commercial POMs has been implemented in 0.5 M H2SO4 (typical electrolyte for those POMs allowing stability of the POM) SiMo12 / SiW12 and PMo12/OW12. Indeed, to maximize the success of the ELECTRA goals, substitution of W by more environmentally friendly atoms like Fe has been performed. Here, Fe4(PW9)2 can be an intriguing choice since a total of 8e- (4 e- from Fe and 4e- from W) can be involved in the redox process with the instability problems inherent in the structure. Under a performance perspective, PV14 and SiV3W9 show many benefits like easy to prepare in contrast to substituted POMs and, additionally, the synthesis yield is notable.
3) Evaluation of PV14; Fe4(PW9)2 and SiV3W9. In deep investigation has been carried out in order to implement the POMs in electrolytes using characterization techniques like FTIR and NMR. The stability of the POMs clusters is quite dependence of the pH. Thus, strong changes in the pH values could provoke a precipitation of the POMs and, in consequence, failure in the battery. ELECTRA project took a new approach with the implementation of the POM in to electrolyte using buffers instead of salts. In that approach, the H+ concentration changes can be mitigated for the action of the buffer. In this framework, it has been found that 1M acetate/acetic pH 3.7 for PV14 and pH 5 for Fe4(PW9)2 was the best one, provinding highly stability. For the case of SiV3W9 only the 3 atoms of V can operate under 1M acetate/acetic pH 5. Finally, the battery with PV14 and Fe4(PW9)2 has been demonstrated, achieving a capacity of 20 mAh. Particularly, the stability of the Fe4(PW9)2 is remarkable allowing the operation up to -1.2V (without the production of hydrogen evolution reaction) and more than 44 hours.
4) Implementation of bipolar electrochemistry into RFB for the first time, providing decrement of the resistance of the cell and allowing higher power densities as well as capacity . It is important to remar that the capacity obtained even surpasses the theoretical capacity of the electrolyte. This fact only can be explained by assuming that the potential induced in the BPE are enough to provide a contrary reaction of the driving electrodes, allowing the regeneration of the vanadium electrolyte.
5) Interfaces characterization and validation of components by employing new methodologies like Synchrotron x-ray absorption spectroscopy: i) Design of the cell specially for measuring in operando synchrotron radiation since it was measure for the first time in Alba facilities, ii) In operando measurements of Fe4(PW9)2..As a conclusion, the FePOM synthesised in ELECTRA project has been evaluated allowing insights of the stability and reversibility as well their structure.
in terms of exploitation and dissemination:The project results will be disseminated in scientific publications, which are under preparation. CF will first and corresponding author of both of them and will be published in Open Access, containing the EU funding.
In parallel, CF has been publishing 4 articles articles taking account her expertise in RFB in collaboration with her network. All publications are Open Access and contain the EU funding.
Conferences: DeCarbon International Conference 2023; EMRS 2022. In addtion it is planed :CF is going to the International Forum Flow Battery (Glasgow, 2024) where she has an accepted talk. In parallel, CF has an invited talk in the 75th Annual Meeting of the International Society of Electrochemistry" (2024, Montréal, Canada) within the symposium Electrochemistry - science and technology for a sustainable and better planet"
In the following points , the highlightes related with the project are indicated:
• Design of new molecules for replacing vanadium in RFB with better properties like multi electron transfer features.
• Stabilization of POM in electrolytes in a mild pH, providing long-term stability
• Implementation of new tools for in situ and in operando measure the stability/degradation of POMs.
• Understanding of the electron transfer process.
• ELECTRA project has been successfully demonstrated all POM battery working with PV14 and Fe4(PW9)2, capable to achieve 20 mAh.
• Taking into account, the performance related with Fe4(PW9)2: 30 mL of 5mM of Fe4(PW9)2 has been discharged up to 40mAh, allowing extremely negative potentials (ca -1.2 V). The solubility on the electrolyte can be increased up to 17.6 mM, a capacity values up to ca. 137,6 mAh can be achieved or 4.6 Ah/L.
• Additionally, Fe4(PW9)2 electrolyte provides excellent cyclability (more than 44 h) without any failure, operating up to -1.2V vs. AgAgCl.
• Bipolar electrochemistry has been demonstrated to be useful tool for improving the power of the RFB as well as the capacity, surpassing the theoretical values.
IMPACT:
According to the Renewables 2020 Analysis and forecast to 2025 (November 2020 by International Energy Agency),the total renewable energy capacity instaled grew by nearly 4% globally in 2020, reaching almost 200 GW, and the total installed power capacity by solar and wind energy will reach 2,349 GW by 2025. Thus, a high performance energy storage are required. In this context, RFB should reduce theircapital cost is and ,hence, the development of alternative RFB technologies is vital. ELECTRA project by the developing new RFB has been contributed to the following poins:
. mitigation of climate change
. Develop disruptive and efficient system with oustanding perfomance, taking account the safety issues (electrolytes with mild pH condiction)
-Decarbonization of transport and energy sector and market opportunities of net-zero systems
• Design of new molecules for replacing vanadium in RFB with better properties like multi electron transfer features.
• Stabilization of POM in electrolytes in a mild pH, providing long-term stability
• Implementation of new tools for in situ and in operando measure the stability/degradation of POMs.
• Understanding of the electron transfer process.
• ELECTRA project has been successfully demonstrated all POM battery working with PV14 and Fe4(PW9)2, capable to achieve 20 mAh.
• Taking into account, the performance related with Fe4(PW9)2: 30 mL of 5mM of Fe4(PW9)2 has been discharged up to 40mAh, allowing extremely negative potentials (ca -1.2 V). The solubility on the electrolyte can be increased up to 17.6 mM, a capacity values up to ca. 137,6 mAh can be achieved or 4.6 Ah/L.
• Additionally, Fe4(PW9)2 electrolyte provides excellent cyclability (more than 44 h) without any failure, operating up to -1.2V vs. AgAgCl.
• Bipolar electrochemistry has been demonstrated to be useful tool for improving the power of the RFB as well as the capacity, surpassing the theoretical values.
IMPACT:
According to the Renewables 2020 Analysis and forecast to 2025 (November 2020 by International Energy Agency),the total renewable energy capacity instaled grew by nearly 4% globally in 2020, reaching almost 200 GW, and the total installed power capacity by solar and wind energy will reach 2,349 GW by 2025. Thus, a high performance energy storage are required. In this context, RFB should reduce theircapital cost is and ,hence, the development of alternative RFB technologies is vital. ELECTRA project by the developing new RFB has been contributed to the following poins:
. mitigation of climate change
. Develop disruptive and efficient system with oustanding perfomance, taking account the safety issues (electrolytes with mild pH condiction)
-Decarbonization of transport and energy sector and market opportunities of net-zero systems