Abstract
Polymeric binders are a critical component to enhance mechanical integrity, maintain electronic conductivity, and achieve long durability of silicon (Si)-based electrodes. A fundamental understanding of the relationship between binder properties and mechanical degradation of Si electrodes is indispensable to developing durable Si-based electrodes. Using an environmental nanoindentation system, we measured the mechanical properties of Si composite electrodes made with different binders, including polyvinylidene fluoride (PVDF), Nafion, sodium-carboxymethyl cellulose (Na-CMC), and sodium-alginate (SA), as a function of the state-of-charge and cycle numbers under both dry and wet conditions. In contrast to electrodes made of Si alone, both elastic modulus (E) and hardness (H) of Si composite electrodes increase with lithium concentration within each cycle. E and H continuously decrease during long-term cycling. The mechanical property evolution of Si composite electrodes can be correlated with the porosity and irreversible thickness changes, which are largely determined by the mechanical properties of binders, instead of the adhesion between binders and Si. Electrodes under wet conditions have smaller E and H values than those under dry conditions because binders soften in the electrolyte. These findings not only provide useful mechanical parameters for battery modeling, but also may help design high performance and durable Si-based electrodes.
Original language | English |
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Pages (from-to) | 170-178 |
Number of pages | 9 |
Journal | Journal of Power Sources |
Volume | 425 |
DOIs | |
State | Published - Jun 15 2019 |
Bibliographical note
Publisher Copyright:© 2019 Elsevier B.V.
Funding
This work is partially supported by the National Science Foundation Award No. 1355438 . The authors also acknowledge the support by the Assistant Secretary for Energy Efficiency and Renewable Energy , Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research (BMR) Program under Contract Number DE-EE0007787 and the financial support from the Alliance for Sustainable Energy, LLC, Managing and Operating Contractor for the National Renewable Energy Laboratory for the U.S. Department of Energy . This work is partially supported by the National Science Foundation Award No. 1355438. The authors also acknowledge the support by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research (BMR) Program under Contract Number DE-EE0007787 and the financial support from the Alliance for Sustainable Energy, LLC, Managing and Operating Contractor for the National Renewable Energy Laboratory for the U.S. Department of Energy.
Funders | Funder number |
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National Science Foundation Arctic Social Science Program | |
U.S. Department of Energy EPSCoR | |
Office of the Director | 1355438 |
Office of Energy Efficiency and Renewable Energy | |
National Renewable Energy Laboratory | |
Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research | DE-EE0007787 |
Keywords
- Electromechanical degradation
- Mechanical property
- Nanoindentation
- Polymeric binder
- Porosity
- Silicon electrode
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering