Periodic Reporting for period 2 - SeNSE (Lithium-ion battery with silicon anode, nickel-rich cathode and in-cell sensor for electric vehicles)
Berichtszeitraum: 2021-08-01 bis 2023-01-31
The SeNSE project aims at enabling a competitive next-generation lithium-ion battery technology for electric vehicles, extending driving range, improving cycling stability, and enabling fast charging, thereby supporting the transition to electric mobility. The project focuses on silicon-graphite composite anodes and a nickel-rich NMC cathodes to reach 750 Wh/L and 2000 deep cycles by reducing the surface reactivity of the active materials by a combination of novel film-forming electrolyte additives and active materials coatings, and by compensating irreversible lithium losses during the first cycles employing pre-lithiated silicon and providing an on-demand reservoir of excess lithium in the cathode. Adaptive fast charging protocols are integrated into the battery management system based on dynamic in-cell sensor data and by implementing thermal management concepts on materials and electrode level. The scalability of the SeNSE battery technology will be demonstrated through 10 Ah pouch cell prototypes and a 0.5 kWh module.
Anode development: Various silicon-graphite composite materials were synthesized and electrochemically characterized in half- and full-cell configuration. The performance of the materials was compared to that of commercially available Si-graphite materials. Furthermore, pre-lithiation strategies were explored and showed great promise to extend cycle life.[1,2] For the first generation SeNSE pouch cells, a selected silicon-graphite anode material was upscaled and an aqueous electrode fabrication process was developed.
Electrolyte development: Several strategies to improve the safety of liquid electrolytes such as addition of ionic liquids or flame retardants were explored and electrolyte formulations were identified that combine high conductivity and low flammability.[3] In addition, several film-forming additives were synthesized and electrolyte formulations containing these additives were identified that improve the cycling stability of (silicon)-graphite/nickel-rich NMC full cells.[4,5] Furthermore, an electrolyte was upscaled for the first generation SeNSE pouch cells.
Cathode development: Ni-rich NMC cathode materials were synthesized and characterized in terms of structure, morphology, and electrochemical properties. In addition, several doping and coating strategies to improve the cycling stability of Ni-rich NMC cathode materials were explored and modification strategies were identified that significantly improve the cycling stability of this class of active materials.[6,7] Furthermore, the use of an alternative conductive additive for the positive electrode was explored and beneficial effects in terms of thermal and electrical properties were found. Finally, several aqueous electrode fabrication processes were developed and one process was upscaled for the first generation SeNSE pouch cells.[8,9]
Sensor development: In-cell sensors for the SeNSE pouch cells were successfully developed. Several reference electrode materials were compared and the best results among the selected materials were obtained for TiO2.[10,11] A sensor array was developed and implemented into the first generation SeNSE pouch cell prototype.
Cell development: The use of thin current collectors was explored. The 10 Ah first generation SeNSE pouch cells incorporating the first generation SeNSE materials including an in-cell sensor array were developed and successfully fabricated.
Module development: The first generation SeNSE module incorporating instrumented first generation SeNSE pouch cells was developed and successfully fabricated.
References:
[1] P. Bärmann et al., Mechanistic insights into the pre-lithiation of silicon/graphite negative electrodes in “dry state” and after electrolyte addition using passivated lithium metal powder, Adv. Energy Mater. 2021, 11, 2100925.
[2] A. Gomez-Martin et al., Opportunities and challenges of Li2C4O4 as pre-lithiation additive for the positive electrode in NMC622||silicon/graphite lithium-ion cells, Adv. Sci. 2022, 9, 2201742.
[3] V. Nilsson et al., Electrolytes with flame retardant pentafluoro(phenoxy)cyclotriphosphazene for nickel-rich layered oxide/graphite cells, Electrochim. Acta 2022, 427, 140867.
[4] C. Wölke et al., Understanding the effectiveness of phospholane electrolyte additives in lithium-ion batteries under high-voltage conditions, ChemElectroChem 2021, 8, 972–982.
[5] B. A. Sadeghi et al, Synergistic role of functional electrolyte additives containing phospholane-based derivative to address interphasial chemistry and phenomena in NMC811||Si-graphite cells, J. Power Sources 2023, 557, 232570.
[6] F. Reissig et al., Synergistic effects of surface coating and bulk doping in Ni-rich lithium nickel cobalt manganese oxide cathode materials for high-energy lithium-ion batteries, ChemSusChem 2021, 15, e202102220.
[7] A. Gomez-Martin et al., Magnesium substitution in Ni-rich NMC layered cathodes for high-energy lithium-ion batteries, Adv. Energy Mater. 2022, 12, 2103045.
[8] M. Heidbüchel et al., Enabling aqueous processing of Ni-rich layered oxide cathode materials by addition of lithium sulfate, ChemSusChem 2022, 16, e202202161.
[9] F. Reissig et al., Investigation of lithium polyacrylate binders for aqueous processing of Ni-rich lithium layered oxide cathodes for lithium-ion batteries, ChemSusChem 2022, 15, e202200401.
[10] Z. Ahmed et al., Ti-Based Reference Electrodes for Inline Implementation into Lithium-Ion Pouch Cells, Energy Technol. 2021, 9, 2100602.
[11] Z. Ahmed et al., Operando thermo-electrochemical diagnostics with Au, TiO2, and LiFePO4 as reference electrodes in Li-ion pouch cells, Energy Technol. 2022, 10, 202200248.
Electrolyte development: Several strategies to improve the safety of liquid electrolytes such as addition of ionic liquids or flame retardants were explored and electrolyte formulations were identified that combine high conductivity and low flammability.[3] In addition, several film-forming additives were synthesized and electrolyte formulations containing these additives were identified that improve the cycling stability of (silicon)-graphite/nickel-rich NMC full cells.[4,5] Furthermore, an electrolyte was upscaled for the first generation SeNSE pouch cells.
Cathode development: Ni-rich NMC cathode materials were synthesized and characterized in terms of structure, morphology, and electrochemical properties. In addition, several doping and coating strategies to improve the cycling stability of Ni-rich NMC cathode materials were explored and modification strategies were identified that significantly improve the cycling stability of this class of active materials.[6,7] Furthermore, the use of an alternative conductive additive for the positive electrode was explored and beneficial effects in terms of thermal and electrical properties were found. Finally, several aqueous electrode fabrication processes were developed and one process was upscaled for the first generation SeNSE pouch cells.[8,9]
Sensor development: In-cell sensors for the SeNSE pouch cells were successfully developed. Several reference electrode materials were compared and the best results among the selected materials were obtained for TiO2.[10,11] A sensor array was developed and implemented into the first generation SeNSE pouch cell prototype.
Cell development: The use of thin current collectors was explored. The 10 Ah first generation SeNSE pouch cells incorporating the first generation SeNSE materials including an in-cell sensor array were developed and successfully fabricated.
Module development: The first generation SeNSE module incorporating instrumented first generation SeNSE pouch cells was developed and successfully fabricated.
References:
[1] P. Bärmann et al., Mechanistic insights into the pre-lithiation of silicon/graphite negative electrodes in “dry state” and after electrolyte addition using passivated lithium metal powder, Adv. Energy Mater. 2021, 11, 2100925.
[2] A. Gomez-Martin et al., Opportunities and challenges of Li2C4O4 as pre-lithiation additive for the positive electrode in NMC622||silicon/graphite lithium-ion cells, Adv. Sci. 2022, 9, 2201742.
[3] V. Nilsson et al., Electrolytes with flame retardant pentafluoro(phenoxy)cyclotriphosphazene for nickel-rich layered oxide/graphite cells, Electrochim. Acta 2022, 427, 140867.
[4] C. Wölke et al., Understanding the effectiveness of phospholane electrolyte additives in lithium-ion batteries under high-voltage conditions, ChemElectroChem 2021, 8, 972–982.
[5] B. A. Sadeghi et al, Synergistic role of functional electrolyte additives containing phospholane-based derivative to address interphasial chemistry and phenomena in NMC811||Si-graphite cells, J. Power Sources 2023, 557, 232570.
[6] F. Reissig et al., Synergistic effects of surface coating and bulk doping in Ni-rich lithium nickel cobalt manganese oxide cathode materials for high-energy lithium-ion batteries, ChemSusChem 2021, 15, e202102220.
[7] A. Gomez-Martin et al., Magnesium substitution in Ni-rich NMC layered cathodes for high-energy lithium-ion batteries, Adv. Energy Mater. 2022, 12, 2103045.
[8] M. Heidbüchel et al., Enabling aqueous processing of Ni-rich layered oxide cathode materials by addition of lithium sulfate, ChemSusChem 2022, 16, e202202161.
[9] F. Reissig et al., Investigation of lithium polyacrylate binders for aqueous processing of Ni-rich lithium layered oxide cathodes for lithium-ion batteries, ChemSusChem 2022, 15, e202200401.
[10] Z. Ahmed et al., Ti-Based Reference Electrodes for Inline Implementation into Lithium-Ion Pouch Cells, Energy Technol. 2021, 9, 2100602.
[11] Z. Ahmed et al., Operando thermo-electrochemical diagnostics with Au, TiO2, and LiFePO4 as reference electrodes in Li-ion pouch cells, Energy Technol. 2022, 10, 202200248.
Various advanced materials including silicon-graphite composites with a silicon content of >10%, non-flammable electrolytes with high conductivity that stabilize silicon-graphite/nickel-rich NMC full cells, and nickel-rich NMC cathode materials have been developed. These battery material solutions enable lithium-ion batteries with high energy density, high cycling stability, and improved sustainability due to lower contents of critical materials. Anode materials with a high silicon content as targeted in the SeNSE project remain a major scientific and technological challenge with regards to cycling stability, but have the potential to significantly increase energy density, improve sustainability, and reduce cost. An effective pre-lithiation approach has been developed that significantly improves cycle life of lithium-ion batteries with silicon-based anodes. In-cell sensors were developed and showed great potential to manage and prevent cell aging by dynamically adapting cycling protocols. The scalability of the SeNSE battery technology has been demonstrated through pouch cell prototypes and battery modules.
The ultimate goal is to strengthen the lithium-ion battery value chain in Europe by contributing innovative solutions on materials, cell, and module level. Scalability to the gigawatt scale and cost-effectiveness of the proposed solutions, including aspects of recycling and second-life use, will be continuously monitored throughout the project.
The ultimate goal is to strengthen the lithium-ion battery value chain in Europe by contributing innovative solutions on materials, cell, and module level. Scalability to the gigawatt scale and cost-effectiveness of the proposed solutions, including aspects of recycling and second-life use, will be continuously monitored throughout the project.