Synthesis and Characterization of Lithium-Ion Based Diatom Batteries

Abstract

New and innovative materials are needed to develop more effective batteries. Nanoscale materials such as graphite have unique properties only seen in the nano-regime that allow them to be used in the production of lithium-ion batteries. For example, because of its ability to conduct electricity, nano-scale graphite has been used in the anode of lithium-ion batteries, which has revolutionized the long-term use of medical devices, such as pacemakers and defibrillators. Interestingly, the graphite anode has a relatively low specific capacity per gram of ~372 mAh g-1, which limits the rate of charge available to these devices. The specific capacity of silicon, however, is ~11 times greater than that of graphite at ~4200 mAh g-1, which makes it a better choice as an anode material. Silicon is not presently used because of its fragility during the lithiation process. In this work, we demonstrate a robust nanoscale material synthesis inspired by the biomineralization process that the ocean-dwelling unicellular phytoplankton, diatoms, that they use to form their porous silicon structure. By maintaining the porous structure of diatoms from the conversion of silica to silicon, using a magnesiothermic reduction process, their structure can be used to enhance silicon’s strength during the lithiation process allowing the use of silicon’s higher specific capacity. This approach has the potential to implement silicon as an anode for lithium-ion batteries to enhance the longevity of present day applications.