The following is a breakdown of the steps being taken to produce Superlattice technology on a mass scale. This will allow Hybrid Technologies to incorporate the technology into a wide range of products, improving their efficiency.
Schedule and Work Breakdown Structure of Proposed Program
Task 1: Synthesis of Proposed Cathode Materials
The objective of this task is to synthesis high capacity cathode materials. A number of variations in heat-treatment temperatures and compositions of the cathode materials will be used in the synthesis process. In this preliminary evaluation, samples will be prepared and delivered to sub-contractors for characterization and performance evaluation. A non disclosures agreement will be signed between all parties to protect technical know-how like cathode material preparation, cell assembly, anode materials, separators and all other components associated with lithium ion batteries.
Task 2: Characterization of Cathode Materials
The primary objective of this task is to characterize the developed cathode materials using analytical and electrochemical techniques. The electrochemical performance of the electrodes in the batteries is critically dependent on several properties such as crystal structure, electronic conductivity, surface area and porosity, i. e., the distribution of micro and macro pores within the electrodes. Therefore, a focus of this project will be to characterize these materials by X-ray diffraction, Scanning electron microscopy, EDS analysis, BET surface area, porosimetry, and particle size distribution in order to correlate physical and chemical properties with their electrochemical performance. The thermal stability of the synthesized materials will also be performed using Thermogravimetric Analysis (TGA) technique.
The X-ray diffraction of the synthesized materials as a function of synthesis temperature will provide the information related to the formation and changes of the crystal structure and minimum temperature. The low temperature is critical in obtaining a high surface area material. Scanning electron micrographs, BET surface area measurements, and the Hg-porosimetry will provide the needed information about the particle size and morphology of the material. EDS analysis will provide a qualitative comparison of different elements present on the surface of the oxides.
Task 3: Fabrication of Cathodes
The objective of this task is to fabricate positive (cathode) electrodes of uniform loading, good mechanical integrity with ease of electrolyte accessibility.
Task 4: Development of Half-Cells and Cells using Appropriate Carbonaceous Anode
The objective of this task is to develop half-cells with the cathode materials and metallic lithium anode in electrolyte.
Initially cylindrical cells, 18650 and/or prismatic 5±0.4 mm (Thick) X 34 mm X 50 mm will be fabricated as per customer’s demand. However, once successful the new lithium ion batteries will be examined for high ampere cells for the use in Hybrid and/or electric vehicles. The most efficient way to fabricate cells and optimization will be conducted by all parties involved in a project with proper non disclosure legal agreements.
After estimating a capacity of at least 10-20% higher than LiCoO2 or present commercially available cathode material Task 5 will be conducted.
Task 5: Evaluation of Performance and Assessment of Technical Feasibility
Some information from customer on cell performance and thermal stability are:
a) Less than 20% capacity loss at 400 cycles @ room temperature. Charge at 1C, rest 10 minutes and discharge at 1C rate. Tap current to 20 mA for a 1.3Ah cell.
b) Safety Test (No Fire/No Explosion):
- Hot Oven Test (130°C for 2 hours)
- Overcharge Test (4.6V @ 3.0A, continue test for 24 hours, or until cell current is <C/10 or until cell temperature is < 30°C
- External short circuit at 60°C, continue test until cell voltage is < 0.1 mV or/and temperature is < 54°C
- Float Charge at 4.2V at 40°C
- Temperature ramp test 20-200°C
Task 6: Final Report
A final report indicating all the experimental procedures, results, critical analysis of the results and recommendation of the future work will be prepared jointly by Hybrid Technologies and participants. We will maintain NDA rules.
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