Among anode materials for lithium ion batteries, silicon (Si) is known for high theoretical capacity and low cost. Si changes volume by 300% during cycling, however, often resulting in fast capacity fade. With sufficiently small Si particles in a flexible composite matrix, the cycle life of Si anodes can be extended. Si anodes also demonstrate stress-potential coupling where the open circuit voltage depends on applied stress. In this paper, we present a NMC-Si battery design, utilizing the undesired volume change of Si for actuation and the stress-potential coupling effect for sensing. The battery consists of one Li(Ni1/3Mn1/3Co1/3)O2 (NMC) cathode in a separator pouch placed in an electrolyte-filled container with Si composite anode cantilevers. Models predict the shape of the cantilever as a function of battery state of charge (SOC) and the cell voltage as a function of distributed loading. Simulations of a copper current collector coated with Si active material show 11.05 mAh of energy storage, large displacement in a unimorph configuration (>60% of beam length) and over 100 mV of voltage change due to gravitational loading.
- Aerospace Division
Multifunctional NMC-Si Batteries With Self-Actuation and Self-Sensing
Ma, J, Rahn, C, & Frecker, M. "Multifunctional NMC-Si Batteries With Self-Actuation and Self-Sensing." Proceedings of the ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. Volume 1: Development and Characterization of Multifunctional Materials; Mechanics and Behavior of Active Materials; Bioinspired Smart Materials and Systems; Energy Harvesting; Emerging Technologies. Snowbird, Utah, USA. September 18–20, 2017. V001T01A010. ASME. https://doi.org/10.1115/SMASIS2017-3886
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