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The surging demand for Li-ion batteries (LIBs) has started a quest for innovations in their design and technology. A notable improvement in this regard involves the use of Silicon (Si) as the active anode material in LIBs. However, a major challenge stopping its widespread adoption is the considerable volume change experienced by Si during the lithiation-delithiation process, leading to volumetric stress-induced capacity degradation. This study identifies three primary capacity fade mechanisms in these LIBs: volumetric-stress-induced cracking and delamination, along with the growth of the solid electrolyte interface (SEI) during charging and discharging cycles. These mechanisms are influenced by battery design and operating conditions, such as Si anode thickness, ambient working temperature, and charging rate, introducing uncertainty into the battery’s degradation rate. In this study, multiple finite element (FE) models are constructed to simulate capacity degradation resulting from these three capacity fade mechanisms and their predictions are validated against experimental data. To address the computational demands of multiple FE models simulating capacity degradation from these fade mechanisms, a Gaussian Process Regression (GPR) surrogate model is developed. This GPR model efficiently predicts capacity fade and is validated for accuracy. Subsequently, the GPR model is used in an uncertainty quantification study that is focused on the battery’s design and operating conditions. The objective is to pinpoint the factors that exert the most significant influence on capacity degradation in Si anode-based LIBs. 

Silicon is an emerging anode material due to its high lithium storage capacity. While some commercial batteries now include silicon particles, porous three-dimensional (3D) scaffolded silicon electrodes may enable higher silicon loading by accommodating the silicon volume expansion during lithiation without significant electrode swelling. However, the electrochemomechanical response of silicon films on metal scaffolds remains poorly understood due to the complex scaffold morphology. We explore the role of scaffold curvature in the cycling behavior of silicon films and show that different curvatures exhibit distinctive failure modes. Negative curvature leads to crack opening from tensile and compressive stresses. Positive curvature induces tensile stress-driven buckling. Zero curvature exhibits fragmentation. The electrode morphology and chemistry for these systems are evaluated via scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDS). COMSOL Multiphysics simulations support that the electrochemo-mechanics of silicon are curvature-dependent. These findings point toward design strategies for 3D architected silicon anodes with improved cycling integrity. 

Ion transport is essential to energy storage, cellular signaling, and desalination. Polymers have been explored for decades as solid-state electrolytes by either adding salt to polar polymers or tethering ions to the backbone to create less flammable and more robust systems. New design paradigms are needed to advance the performance of solid polymer electrolytes beyond conventional systems. Here, the role of a helical secondary structure is shown to greatly enhance the conductivity of solvent-free polymer electrolytes using cationic polypeptides with a mobile anion. Longer helices lead to higher conductivity, and random coil peptides show substantially lower conductivity. The macrodipole of the helix increases with peptide length leading to larger dielectric constants. The hydrogen bonding of the helix also imparts thermal and electrochemical stability, while allowing for facile dissolution back to monomer in acid. Peptide polymer electrolytes present a promising platform for the design of next generation ion transporting materials. 

Redox-active colloids (RACs) represent a novel class of energy carriers that exchange electrical energy upon contact. Understanding contact-mediated electron transfer dynamics in RACs offers insights into physical contact events in colloidal suspensions and enables quantification of electrical energy transport in nonconjugated polymers. Redox-based electron transport was directly observed in monolayers of micron-sized RACs containing ethyl-viologen side groups via fluorescence microscopy through an unexpected nonlinear electrofluorochromism that is quantitatively coupled to the redox state of the colloid. Via imaging studies, using this electrofluorochromism, the apparent charge transfer diffusion coefficientD_CTof the RAC was easily determined. The visualization of energy transport within suspensions of redox-active colloids was also demonstrated. Our work elucidates fundamental mechanisms of energy transport in colloidal systems, informs the development of next-generation redox flow batteries, and may inspire new designs of smart active soft matter including conductive polymers for applications ranging from electrochemical sensors and organic electronics to colloidal robotics.