Periodic Reporting for period 3 - Si-DRIVE (Silicon Alloying Anodes for High Energy Density Batteries comprising Lithium Rich Cathodes and Safe Ionic Liquid based Electrolytes for Enhanced High VoltagE Performance.)
Reporting period: 2022-02-01 to 2023-07-31
Widespread market acceptance of electric vehicles (EVs) centres on advances in rechargeable batteries across price, performance, safety, recyclability and suitability for fast charging. Increased adoption of EVs, stimulated by the innovations developed within Si-DRIVE will be an integral part of a greener economy.
Objectives of Si-DRIVE: 1. Development of safe & manufacturable LIB with Si anodes, IL-based solid polymer electrolytes & Li rich cathodes. 2: Achieve beyond SoA full-cell level EDs in two generations. Gen 1: 300-350 Wh/Kg, Gen 2: 350-400 Wh/Kg, providing a pathway to > 450 Wh/kg by 2030. 3: Show capability for fast charging. Gen 1: 2C, 30 mins charge. Gen 2: 6C, 10 mins charge. 4: Demonstrate 500 full-cell cycles (Gen 1) and 1000 cycles (Gen 2) with 80% capacity retention. 5: Show the high sustainability of this new technology and the related cost effectiveness by the application of LCA and LCC approaches and economic viability of recycling with an efficiency >50 weight %. 6: Develop a 2nd life business plan and economic model built upon demonstrator.
Objectives of Si-DRIVE: 1. Development of safe & manufacturable LIB with Si anodes, IL-based solid polymer electrolytes & Li rich cathodes. 2: Achieve beyond SoA full-cell level EDs in two generations. Gen 1: 300-350 Wh/Kg, Gen 2: 350-400 Wh/Kg, providing a pathway to > 450 Wh/kg by 2030. 3: Show capability for fast charging. Gen 1: 2C, 30 mins charge. Gen 2: 6C, 10 mins charge. 4: Demonstrate 500 full-cell cycles (Gen 1) and 1000 cycles (Gen 2) with 80% capacity retention. 5: Show the high sustainability of this new technology and the related cost effectiveness by the application of LCA and LCC approaches and economic viability of recycling with an efficiency >50 weight %. 6: Develop a 2nd life business plan and economic model built upon demonstrator.
Anode Development: Anodes have been developed by UL and Smit Thermal consisting of amorphous silicon deposited onto current collectors consisting of copper silicide nanowires grown from a copper foil. The porosity of the amorphous silicon anode coating was controlled by Smit Thermal through the hydrogen source content. Anodes have been prepared in large areas (6 x5 cm) and tested with ionic liquid electrolytes and in full cells versus high voltage lithium rich cathodes.
Electrolyte Development: Overall WP2 target is the development of high purity, anhydrous, ionic liquid-based electrolytes, both liquid (Gen 1) and solid (Gen 2). The former will be housed within proper polymer hosts. The developed electrolyte systems have to match the following targets: extremely low volatility, non-flammability, high conductivity (> 1 mS cm-1 at 20 °C and > 0.1 mS cm-1 at –10 °C), high anodic stability (> 4.5 V (vs. Li+/Li°), high thermal stability (> 150 °C), good compatibility (in terms of cycling performance) with large capacity silicon anodes and high voltage lithium-rich nickel manganese oxide cathodes, industrial up-scalability. Finally, proper amounts have to be provided for the prototype manufacturing.
Within WP3 of Si-DRIVE new LRLO cathode materials are developed with the primary goal to eliminate Co from the structure. In order to subsequently further improve the performance of the material, i.e. avoid structural decay and the corresponding fading of capacity and voltage, specific dopants are introduced to stabilize the Li-deficient layers at high state of charge. Finally, protective coatings are investigated to avoid the transformation starting from the surface into the bulk structure, as well as to prevent oxidative decomposition of the electrolyte at high potentials allowing the use of ionic liquids and to enable the aqueous electrode processing of the LRLO cathodes.
WP4: From the beginning of the project, aqueous-based Gen0 and Gen1 Li-rich layered oxides (LRLO) cathodes were processed and characterised, showing comparable electrochemical performance to electrodes prepared from conventional organic based slurries (NMP as solvent). Full cell characterisation of SI-DRIVE chemistry resulted on cells with a cycle life of 200 cycles > 80%SOH with areal capacity of 1.5 mAh/cm2. The most suitable components were identified for Gen1 prototype pouch cells: organic LRLO cathode, Si/Gr anode and carbonate-based electrolyte.
Component Modelling: On the cathode side, a computational description of the structure, the electronic properties and the thermodynamic and structural stability of cathode materials based on LRLO oxides (with formula Li1.2Ni0.2-x/2Mn0.6-x/2CoxO2 where x= 0.12 0.08 0.04 and 0) was developed by means of DFT calculations.
End of Life, LCC & LCA: So far there are no pouch cells available for post-mortem analysis and aging analysis in 6.3. First investigations, performed on cycled cathode materials (from coin cells) show structural degradation. Driving profile (by CRF) on fast charge was tested in coin cell format at CID. 1 kg of LRLO material was synthesized for RWTH Aachen for starting recycling activities.
Project Dissemination, Exploitation, Communication & Management: Exploitable results were identified in each work package. From a management point of view, activities continued on the project via a specialist EU project manager.
Electrolyte Development: Overall WP2 target is the development of high purity, anhydrous, ionic liquid-based electrolytes, both liquid (Gen 1) and solid (Gen 2). The former will be housed within proper polymer hosts. The developed electrolyte systems have to match the following targets: extremely low volatility, non-flammability, high conductivity (> 1 mS cm-1 at 20 °C and > 0.1 mS cm-1 at –10 °C), high anodic stability (> 4.5 V (vs. Li+/Li°), high thermal stability (> 150 °C), good compatibility (in terms of cycling performance) with large capacity silicon anodes and high voltage lithium-rich nickel manganese oxide cathodes, industrial up-scalability. Finally, proper amounts have to be provided for the prototype manufacturing.
Within WP3 of Si-DRIVE new LRLO cathode materials are developed with the primary goal to eliminate Co from the structure. In order to subsequently further improve the performance of the material, i.e. avoid structural decay and the corresponding fading of capacity and voltage, specific dopants are introduced to stabilize the Li-deficient layers at high state of charge. Finally, protective coatings are investigated to avoid the transformation starting from the surface into the bulk structure, as well as to prevent oxidative decomposition of the electrolyte at high potentials allowing the use of ionic liquids and to enable the aqueous electrode processing of the LRLO cathodes.
WP4: From the beginning of the project, aqueous-based Gen0 and Gen1 Li-rich layered oxides (LRLO) cathodes were processed and characterised, showing comparable electrochemical performance to electrodes prepared from conventional organic based slurries (NMP as solvent). Full cell characterisation of SI-DRIVE chemistry resulted on cells with a cycle life of 200 cycles > 80%SOH with areal capacity of 1.5 mAh/cm2. The most suitable components were identified for Gen1 prototype pouch cells: organic LRLO cathode, Si/Gr anode and carbonate-based electrolyte.
Component Modelling: On the cathode side, a computational description of the structure, the electronic properties and the thermodynamic and structural stability of cathode materials based on LRLO oxides (with formula Li1.2Ni0.2-x/2Mn0.6-x/2CoxO2 where x= 0.12 0.08 0.04 and 0) was developed by means of DFT calculations.
End of Life, LCC & LCA: So far there are no pouch cells available for post-mortem analysis and aging analysis in 6.3. First investigations, performed on cycled cathode materials (from coin cells) show structural degradation. Driving profile (by CRF) on fast charge was tested in coin cell format at CID. 1 kg of LRLO material was synthesized for RWTH Aachen for starting recycling activities.
Project Dissemination, Exploitation, Communication & Management: Exploitable results were identified in each work package. From a management point of view, activities continued on the project via a specialist EU project manager.
Anode Development : There has been significant progress beyond the state of the art particularly in terms of the dimensions of the anodes that are achievable and the ability to tune the mass loading of amorphous silicon on the wires. Towards the end of the project these anodes will be integrated into full cells with optimised electrolyte formulations and high voltage lithium rich cathodes. Anode prelithiation will also be investigated. This research makes silicon commercially viable as an anode material for lithium ion allowing for increases in energy density that will translate into range increases for EVs, faster charging times and increased lifetimes.
Electrolyte Development: as per 1st Technical Report the 0.2LiTFSI-0.8EMITFSI and 0.2LiTFSI-0.8EMIFSI electrolytes were seen to satisfy the Si-DRIVE targets. Therefore, they were screened as the most promising ones for the Gen1 formulation and selected for the electrochemical testing with nanowire (NW) Si anodes provided by the University of Limerick (UL) and LMNO cathodes provided by KIT. Analogously, EHIFSI and EHITFSI were selected as the most promising PIL additives for improving the interfacial compatibility of the electrolytes towards Si anodes. On the anode side, the results show that EMIFSI-based electrolytes behave much better with respect to the EMITFSI-ones, due to very good film-forming ability onto Si anodes and faster ion transport properties of the FSI anion.
Cathode Development: During the second reporting period (M19 – M37) the lab-scale LRLO was under further development towards the use of safe ionic liquid (IL)-based electrolytes and the aqueous electrode processing through the application of protective surface coatings/treatments. The work on IL-based electrolytes specifically focused on stabilizing the LRNM cathode surface via the in-situ formation of a stable cathode electrolyte interphase (CEI) layer that would suppress structural degradation of the material
Full Cell Testing : Aqueous processed LRLO cathodes with high specific capacity and cycle life provide lower environmental impact than organic based cathodes. Also, cell prototyping of Si-DRIVE full cell components at pouch cell level will provide outcomes to demonstrate this technology at TRL 4-5 for later development of the technology at higher TRLs.
Component Modelling: Besides the scientific results obtained within the project, it can be cited that some methodological progress beyond the state of the art has been obtained from DFT calculations and atomistic modelling.
Electrolyte Development: as per 1st Technical Report the 0.2LiTFSI-0.8EMITFSI and 0.2LiTFSI-0.8EMIFSI electrolytes were seen to satisfy the Si-DRIVE targets. Therefore, they were screened as the most promising ones for the Gen1 formulation and selected for the electrochemical testing with nanowire (NW) Si anodes provided by the University of Limerick (UL) and LMNO cathodes provided by KIT. Analogously, EHIFSI and EHITFSI were selected as the most promising PIL additives for improving the interfacial compatibility of the electrolytes towards Si anodes. On the anode side, the results show that EMIFSI-based electrolytes behave much better with respect to the EMITFSI-ones, due to very good film-forming ability onto Si anodes and faster ion transport properties of the FSI anion.
Cathode Development: During the second reporting period (M19 – M37) the lab-scale LRLO was under further development towards the use of safe ionic liquid (IL)-based electrolytes and the aqueous electrode processing through the application of protective surface coatings/treatments. The work on IL-based electrolytes specifically focused on stabilizing the LRNM cathode surface via the in-situ formation of a stable cathode electrolyte interphase (CEI) layer that would suppress structural degradation of the material
Full Cell Testing : Aqueous processed LRLO cathodes with high specific capacity and cycle life provide lower environmental impact than organic based cathodes. Also, cell prototyping of Si-DRIVE full cell components at pouch cell level will provide outcomes to demonstrate this technology at TRL 4-5 for later development of the technology at higher TRLs.
Component Modelling: Besides the scientific results obtained within the project, it can be cited that some methodological progress beyond the state of the art has been obtained from DFT calculations and atomistic modelling.