Anode development: An innovative cost-effective method for the synthesis of silicon-graphite composite anode materials with a silicon content of >10% was developed and materials were characterized electrochemically in half- and full-cell configuration. The production of selected silicon-graphite composite anode materials was upscaled to industrial pilot scale to enable their integration into 12 Ah SeNSE prototype pouch cells. Silicon pre-lithiation was shown to extend cycle life by a factor of 2 [1-3].
Electrolyte development: Several strategies to improve the safety of liquid electrolytes such as the addition of ionic liquids or flame retardants were explored and electrolyte formulations were identified that combine high lithium-ion conductivity and low flammability.[4,5] In addition, several film-forming additives were synthesized and electrolyte formulations containing these additives were identified that improve the cycling stability of full cells with (silicon)-graphite anode and a nickel-rich layered oxide cathode.[6,7] Furthermore, the synthesis of multiple additives developed in the SeNSE project was upscaled to industrial pilot scale.
Cathode development: Nickel-rich layered oxide cathode materials with a cobalt to nickel ratio <10% were synthesized and characterized in terms of structure, morphology, and electrochemical properties. To improve cycling stability, several doping and protective coating strategies were explored and modification strategies were identified that significantly improve the cycling stability.[8-11] A selected coated nickel-rich layered oxide cathode material was upscaled to pilot scale to enable integration into 12 Ah SeNSE prototype pouch cells.
Electrode development: As an alternative to traditional electrode manufacturing processes employing toxic solvents, aqueous electrode manufacturing processes were developed and scaled for the negative and positive electrode including also an aqueous process for the protective coating of the nickel-rich layered oxide cathode materials. [12,13] The use of an alternative conductive additive for the positive electrode was also explored and beneficial effects in terms of thermal and electrical properties were identified.
Cell development: In-cell sensor arrays measuring temperature and potential were successfully developed and integrated into 12 Ah SeNSE prototype pouch cells. Several reference electrode materials were compared with titanium dioxide-based electrodes delivering the most reliable result.[14,15]
Module development: A modular 0.5 kWh SeNSE smart battery module incorporating twelve instrumented 12 Ah SeNSE prototype pouch cells was developed. The in-cell sensor arrays were key to reach the fast-charging target of 2.5C by providing the battery management system with real-time data enabling adaptive cooling strategies.
While the COVID-19 pandemic effected the project and certain tasks had to be reallocated to other members of the consortium including new members, delays could be compensated in the second half of the project.
References:
[1] Adv. Energy Mater. 2021, 11, 2100925.
[2] Adv. Sci. 2022, 9, 2201742.
[3] Adv. Energy Sustainability Res. 2024, 5, 2300177.
[4] Electrochim. Acta 2022, 427, 140867.
[5] Batteries Supercaps 2023, 6. e202300220.
[6] ChemElectroChem 2021, 8, 972.
[7] J. Power Sources 2023, 557, 232570.
[8] ChemSusChem 2021, 15, e202102220.
[9] Adv. Energy Mater. 2022, 12, 2103045.
[10] Batteries 2023, 9, 245.
[11] Electrochim. Acta 2023, 462, 142758.
[12] ChemSusChem 2022, 15, e202200401.
[13] ChemSusChem 2022, 16, e202202161.
[14] Energy Technol. 2021, 9, 2100602.
[15] Energy Technol. 2022, 10, 202200248.
