The performance of current commercial Li-ion batteries with graphite anodes is limited by the relatively small amount of lithium that can reversibly intercalate between the graphite layers. To make batteries with capacities higher than the theoretical maximum for intercalation, new materials must be found which can react reversibly and quickly with large quantities of lithium while maintaing structural integrity and electrical conductivity. Silicon is a very promising material because it can react with up to 3.75 equivalents of lithium. The structural changes that occur during charging and discharging of Li-Si batteries are poorly understood - this study will use Reverse Monte Carlo methods on neutron diffraction data from samples taken from selected points on the charge-discharge curve to further our understanding of the charge-discharge process.