Experimental Characterization and Predictive Modeling of 100% Silicon Nanowire Anode Pouch Cells

Abstract

The need for next-generation energy storage technologies has made silicon a leading prospect for next-generation anode materials in lithium-ion batteries, due to its theoretical capacity nearly ten times that of conventional graphite. However, the actual application of silicon has faced significant physical challenges, notably extreme mechanical degradation and rapid capacity fading due to the large volume expansion of silicon upon lithiation. This thesis discusses a comprehensive study and modeling of these behaviors in full pouch-type cells with 100\% silicon nanowire (SiNW) anodes.

To achieve this, a multiphysics framework was developed that combined rigorous experimental characterization with advanced computational modeling. A custom designed isothermal calorimeter allowed precise quantification of the electrochemical and thermal behavior of the cells in different C-rates (C/10, C/5, and C/3) and temperatures (10°C, 25°C, and 50°C). Simultaneously, a physics-based reduced order model (ROM) was developed to represent the coupled electrochemical, thermal, and mechanical behaviors.

The model was validated by comparison with the experimental results, showing accurate prediction of the cell voltage behavior and heat generation rate (HGR), with a root-mean-square error (RMSE) below 30 mV for all C-rates and temperatures considered. This work provides valuable insight into the performance of pure SiNW anodes in a full cell configuration, with a validated modeling framework that may enable the development of high-capacity lithium-ion batteries in future applications.