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Hybrid power-energy electrodes for next generation lithium-ion batteries

Periodic Reporting for period 1 - Hydra (Hybrid power-energy electrodes for next generation lithium-ion batteries)

Reporting period: 2020-05-01 to 2021-10-31

Electric mobility has become an important foundation for the future of European industry and society. Electric vehicles require high-performance batteries that can store a large amount of energy and be charged quickly. Furthermore, these batteries must use sustainably sourced materials to avoid supply chain bottlenecks and price fluctuations. The battery landscape is quickly shifting to meet these challenges, but some fundamental obstacles remain.

HYDRA aims to develop the next generation of commercially viable Li-ion battery cells based on sustainable materials and manufacturing processes. Within the roadmap for future battery development, these Li-ion battery cells are referred to as generation 3b. They aim to increase the energy density of the cells by developing new materials, while also reducing the critical raw materials (CRM) content by more than 85%. To achieve this goal, high-capacity silicon is blended together with graphite in the anode and cobalt-free lithium nickel manganese oxide (LNMO) and lithium iron phosphate (LFP) materials are used in the cathode.

The problem is that although these materials can improve the energy density of the battery, they typically suffer from accelerated capacity loss over cycling. HYDRA brings together leading industry and research partners to identify novel solutions to extend the cycle life of these cells and support the growing European battery industry. By the end of the project in 2024, HYDRA aims to demonstrate cells with high energy density (>750 Wh/L) and long cycle life (>2000 cycles) while supporting fast charging from 20% - 80% SOC in 8-12 min. Through the development of sustainable and high-performance Li-ion cells, HYDRA will contribute to the future of electric mobility and help support the Green Transition.

Throughout the work foreseen in the project, it is very important to engage with both the European battery community and the public. HYDRA aims to support the community by making as much data as possible available using the FAIR data standards. Furthermore, the modelling tools developed in the project will be made open-source. In the latter phases of the project, HYDRA aims to interact directly with researchers from around Europe via the Access HYDRA program, in which researchers, engineers, or students can apply for short research stays at HYDRA partner institutes to develop skills or knowledge related to the project objectives.
The first phase of the project has focused on (i) creating digital tools to model and simulate cell performance, (ii) producing the first generation of HYDRA cells to serve as a platform for development, and (iii) benchmarking materials performance and evaluating the success of proposals to increase their performance.

Batteries are complex systems. In HYDRA, researchers are developing new cutting-edge modelling tools that provide the insight needed to better understand cell performance, while also being easy to use even for researchers and engineers without a deep background in modelling. One example developed in the first period of the project is the BatMo continuum modelling framework. BatMo allows researchers to peek inside the cell and see how critical quantities like concentration, temperature, and electric potential develop over time. The initial version will be publicly launched in Spring of 2022.

The first period has also seen the production of the first batch of HYDRA 10 Ah pouch cells! The purpose of this first generation of HYDRA.0 cells is to benchmark the performance at the start of the project and provide a platform to build future developments on. Full characterization is on-going and will be the subject of an upcoming publication. In parallel, HYDRA partners are pursuing the development of new materials for the next phase of the project, HYDRA.1. This includes the possibility to blend LNMO with LFP to offer some surface protection, pursuing aqueous processing of LNMO electrodes for reduced cost and improved sustainability, investigating new methods to blend Si with graphite, and identifying stable electrolyte formulations. Sustainability is a central focus in this activity. The HYDRA partners have participated in a Battery Ecodesign Workshop to learn methods for integrating sustainability considerations into battery development and identify critical areas of battery development that could greatly benefit from Ecodesign considerations.

The next phase of the project will focus on demonstrating the HYDRA.1 generation in pouch cell format. This should put the project within striking distance of its goals for the final HYDRA.2 generation in the final phase of the project.
HYDRA aims to advance beyond the state of the art in at least 4 areas: cathode materials, anode materials, electrolytes, and sustainable scale-up.

The development of cathode materials in HYDRA seeks to circumvent the problems that have so-far limited the performance of high-voltage spinel materials like LNMO. HYDRA's approach of using surface treatment layers on LNMO to increase cell power and to avoid cation dissolution is environmentally friendly, and the performance goals will be reached with no use of the CRM cobalt. Strong focus on the scalability of the approach will maximize the chances of industrial realisation.

Anode material development in HYDRA will seek to maximize the capacity of the electrode by blending significant amounts of Si with graphite. HYDRA will develop composites with low area/volume ratio and high cycling stability. In an optimised binder-system, these composites will give high energy density with the required cycling stability necessary for industrial relevance.

Electrolytes must be able to support the unique processes at both electrodes while also being very stable and highly ionically conductive. HYDRA will develop new electrolyte systems that function at the high working voltages of our proposed high voltage cathode materials, while also being compatible with the Si-graphite anode by passivating the Si surface from continuous electrolyte reduction.

As giga-scale production of batteries is growing across Europe, the use of sustainable manufacturing processes is more important than ever. HYDRA will develop solutions for all-aqueous based electrodes for Li-ion HYBRID batteries and demonstrate them in pilot scale. The water-based chemistries will reduce the need for dry-rooms, decreasing manufacturing energy consumption. This will provide the environmentally friendly and economically sustainable production processes necessary to obtain the high energy, next gen.3b Li-ion batteries necessary for a decarbonised Europe.

Taken together, these individual improvements on the state of the art will lead to a new generation of Li-ion battery cells with not only beyond state of the art performance KPIs for energy density and cycle life, but also sustainably based manufacturing processes and model-accelerated development workflows. This is essential to establishing a successful and environmentally friendly battery industry in Europe. In pursuit of this goal, HYDRA will also educate the up-and-coming generation of scientists and engineers by supporting students, post-docs, and early career researchers in the project. As the demand for batteries increases around the world, HYDRA will position European society to benefit from the Green Transition in terms of education, jobs, access to clean energy, and improved environmental quality.
Participants at the HYDRA Battery Ecodesign Workshop in Grenoble, France. November 2021.
HYDRA.0 cells ready for shipment
Brainstorming at the HYDRA Battery Ecodesign Workshop in Grenoble, France. November 2021.
HYDRA Partners at the 2nd Biannual Meeting in Grenoble, France. November 2021.