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Metal oXide high energy Capacitors

Periodic Reporting for period 1 - X-CAP (Metal oXide high energy Capacitors)

Reporting period: 2020-08-01 to 2021-07-31

The problem we address
The struggle to reduce overall carbon emissions and the electrification of stationary and mobile applications has increased the need for energy storage technologies such as fuel cells (FCs), Lithium Ion batteries (LIBs) and Ultracapacitors. However, upon analyzing the qualities of these energy storage technologies, a clear techno-economical gap becomes evident which can be filled by an energy storage technology with low energy cost (<250 EUR/kWh), high power (>10 kW/kg) and medium energy density (>50 Wh/kg), as well as an operating temperature window of -40°C to +70°C.

Our impact for society
With this gap currently left unfilled, there are a range of applications in which electrification cannot be realized at reasonable consumer price ranges, introducing a significant market barrier for high GHG reduction impact. In LIB-X-Cap hybrid vehicles the size and power ratings for the main battery can be reduced, resulting in a significant cost-down for battery-electric vehicles s and thus bringing the electric vehicle solution to consumer segments which are unable to afford a state-of-the-art small electric vehicle, e.g. a Nissan Leaf.
Furthermore, an energy storage system able to fill this technological gap would be able to replace a century old technology still present today in every road-going vehicle: Lead Acid batteries (LAB). To the 2 million people involved in LAB recycling in 3rd world countries, the heavy metals contained in LABs are estimated to cost 2-4.5 million years of life each year. The recycling of X-Cap batteries would not involve working with toxic chemicals, as their recycling concept is similar to that of Ultracapacitors.

Our overall objectives
The X-CAP technology will, as a first-in-kind approach, directly address this gap of 15 min energy storage applications in the energy storage market. X-CAP is an energy storage device which fills the gap between high energy density technologies such as LIBs and high power density technologies such as Ultracapacitors while providing a much longer lifetime (>200,000 cycles) than LIBs themselves and being independent of critical resources or heavy metals.
Skeleton has proven that the concept of this energy storage technology can deliver the envisioned product characteristics and is now targeting product development to bring this innovation to the market. Within the proposed project, Skeleton aims to develop this technology from current TRL of 6 to TRL 8.
Thus far, Skeleton has worked in work packages 1, 2, 3 and 5 in line with the project plan. During this time, Skeleton has reached milestones M1.1 (Additional automotive customer LoI signed, due July 31st, 2021) and has handed in deliverables D1.1 (Customer requirements and techno-economic analysis report, due April 30th, 2021) and D 2.1 (Electrode design report, due July 31st, 2021)
Work Package 1: Techno-economic analysis and business development
Skeleton was able to discuss the X-Cap technology with several new business contacts: Wrightbus, Hyzon Motors, Hyperion Motors, Faurecia, Valeo, Leoni, Ferrari, Ford, ZF Friedrichshafen and Magna Steyr.
With this progress in WP1, we have reached milestone M1.1 on time by signing an LOI with Dancerbus on April 14th, 2021.
Skeleton Technologies has also entered into a development agreement with BMW regarding the development of X-CAP technology for automotive applications.
Work Package 2: Optimization of electrode material choice and electrode technology pilot
Skeleton Technologies R&D team has focused on the evaluation of several raw material grades to be incorporated into industrial composite type electrodes, as well as finding new contacts for possible higher-grade materials.
Work Package 3: Cell design optimization
WP 3 started in April 2021, where we continue hybrid material discussions to define further process parameter requirements in order to reach a suitable level of oxide coating on substrate carbon material while not compromising with extensive pore blocking.
Work Package 5: Use case environment testing
The first electrode pilot coating in progress, with large industrial cylindrical cell prototypes (>5 Ah) assembled for testing at device level based on the results shown above. To further understand the way forward, it is key to transfer lab-scale data as soon as possible to production cells to eliminate possible cell effects. For that we will establish several pilot coatings with different set of materials and coating thicknesses for balancing purpose.
Progress beyond the state of the art
Ultracapacitors store energy through charge separation in the electrochemical double layer (EDL). Since the EDL only forms on the surface of the electrode material, the energy density of Ultracapacitors (or electrochemical double layer capacitors, EDLCs) is limited by the available surface area of the electrode material.
The innovation proposed in X-CAP overcomes this physical limitation of energy storage in Ultracapacitors and enabling more than 10 times increased energy storage compared to today’s available products by introducing redox-active components into the electrodes, which then can store more energy than could be achieved by classical double layer storage.
Skeleton has developed 2 main pathways for the integration of metal oxides into Ultracapacitor electrodes: Hybrid materials and composite materials. Both composite and hybrid materials are viable options for increasing an Ultracapacitor’s energy content beyond classic double layer barriers.
Expected results until the end of the project
The technology is identified to be at TRL6, as the successful coating on aluminum foil in a roll-to-toll process displays the readiness for roll-to-roll coating in a pilot environment and subsequent cell prototype manufacturing, using otherwise known and established materials and processes for separator, cell construction and electrolyte.
At the end of the project, the technology is expected to be at TRL 8.
Potential impacts (including the socio-economic impact and the wider societal implications of the project so far)
Societal needs in industrial, grid and automotive sector have one common denominator: the cost of energy storage paired with fast charging capabilities and long lifetime.
The transition from fossil to renewable energies has its bottleneck in energy storage. Energy consumers expect unlimited, reliable energy, which is faced with challenges due to the volatility of renewable energy sources. Here, X-Caps can have significant positive impact on the nexus of social and economic behavior which affects the climate and the environment
In addition, the Großröhrsdorf facility where X-Cap will be developed and produced is located in a former coal mining region in East Germany, near the Czech boarder. Skeleton has chosen this site due to our commitment to further a just energy transition, not only in our technology, but in an effort to bring clean, safe, and permanent jobs to a region in transition.
Picture of an X-Cap