Khái niệm cốt lõi
Chemo-mechanical modelling is a crucial tool for understanding and improving the performance and lifetime of current and next-generation battery technologies, addressing key challenges such as diffusion-induced stress, volumetric strains, and dendrite growth.
Tóm tắt
The content provides an overview and perspective on the role of chemo-mechanical modelling in the development of battery technology. It highlights the importance of considering solid mechanics, in addition to electrochemistry, transport, and thermodynamics, to fully understand the complex operating mechanisms of batteries.
The key points are:
- Diffusion-induced stress and volumetric strains in active materials, as well as the initiation and growth of voids and lithium dendrites, are critical issues that can lead to battery degradation and failure. Chemo-mechanical modelling is essential for addressing these challenges.
- The content outlines the fundamental equations that link electrochemistry and mechanics, and discusses the importance of appropriate constitutive formulations, fracture modelling, and material property measurements in chemo-mechanical models.
- Chemo-mechanical models are developed at multiple scales, from single particles to entire electrodes, to provide insights into the complex deformation and failure mechanisms in batteries.
- Continued interdisciplinary collaboration and the integration of computational modelling and experimental validation are crucial for advancing chemo-mechanical research and its application in battery technology.
- The increasing focus on solid-state batteries requires significant attention to chemo-mechanical phenomena, such as pulverization of alloy anodes, dendrite growth, and interfacial contact loss, which must be addressed through chemo-mechanical modelling and experiments.
Thống kê
Lithiation-induced strain, ε_L, is typically given by the expression: ε_L = 1/3 Ω(c-c_0)I, where Ω is the partial molar volume, c is the lithium concentration, c_0 is the initial lithium concentration, and I is the identity tensor.
The chemical potential, μ, is affected by the hydrostatic stress, σ_H, according to the equation: μ = μ_0 + RT ln(c/(c_max-c)) - Ω σ_H.
The diffusive flux, J, of lithium in the active materials is also affected by the hydrostatic stress, as shown by the equation: J = -D(∇c - Ω c/(RT)∇σ_H), where D is the diffusion coefficient.
Trích dẫn
"If diffusion-induced stresses and volumetric straining occurs during operation, battery capacity can be directly affected by increasing or decreasing the overpotentials, since overpotential is related directly to the electrochemical potential."
"Fracture plays a central role in the long-term stability of battery materials, and it is crucial that it is considered from a modelling perspective."
"Technological development of battery systems requires the intersection of computational modelling and experiment; experiments fulfil the crucial role of physical insight, while also providing the basis for computational models that provide a cost-effective way of design and optimisation as well as enabling further physical insight."