| AVS 64th International Symposium & Exhibition | |
| Thin Films Division | Monday Sessions |
| Session TF+EM-MoM |
| Session: | ALD for Energy Conversion, Storage, and Electrochemical Processes |
| Presenter: | Kevin Laughlin, Brigham Young University |
| Authors: | K. Laughlin, Brigham Young University E. Laughlin, Brigham Young University R. Fan, Brigham Young University R.F. Davis, Brigham Young University R.R. Vanfleet, Brigham Young University J. Harb, Brigham Young University |
| Correspondent: | Click to Email |
Here we present work on a hierarchical approach to structuring and encapsulating carbon nanotube (CNT) based carbon monoliths. Prior work has shown silicon has high gravimetric capacity, but increases by ~300%, and forms an unstable solid electrolyte interphase (SEI). High stability and lifetime operation requires nanostructuring of the silicon to alleviate stresses caused by the large expansion of the silicon upon Li alloying, and an encapsulation layer to restrict SEI build up. These CNT structures provide: porous scaffolding for silicon to expand to manage stress on multiple scales, a long conductive path for lithium transfer resulting in tall electrodes, and protection from unstable SEI formation. At high silicon loadings even nanoscale layers of silicon result in stresses large enough to cause mechanical damage to the electrode and encapsulation layer, resulting in lower capacity and cell lifetimes. By patterning the CNT scaffolding, we can contain the stresses caused by lithiation.