Michael W. Forney

Prelithiation of Silicon–Carbon Nanotube Anodes for Lithium Ion Batteries by Stabilized Lithium Metal Powder (SLMP)

Stabilized lithium metal powder (SLMP) has been applied during battery assembly to effectively prelithiate high capacity (1500-2500 mAh/g) silicon-carbon nanotube (Si-CNT) anodes, eliminating the 20-40% first cycle irreversible capacity loss. Pressure-activation of SLMP is shown to enhance prelithiation and enable capacity matching between Si-CNT anodes and lithium nickel cobalt aluminum oxide (NCA) cathodes in full batteries with minimal added mass. The prelithiation approach enables high energy density NCA/Si-CNT batteries achieving >1000 cycles at 20% depth-of-discharge.

Advanced germanium nanoparticle composite anodes using single wall carbon nanotube conductive additives

The morphology, thermal stability, impedance, and rate performance of germanium nanoparticle (Ge-NP) based lithium ion battery electrodes that incorporate single-walled carbon nanotube (SWCNT) conductive additives has been systematically studied for varying SWCNT loadings (1–3% w/w SWCNT) and electrode areal capacities (4–12 mA h cm−2). Scanning electron microscopy (SEM) was used to characterize the surface coverage for carbon black and SWCNT conductive additives. Differential scanning calorimetry (DSC) analysis shows a 30% reduction in exothermic release with SWCNT conductive additives, which demonstrates improved thermal stability for Ge-NP electrodes. Electrochemical impedance spectroscopy (EIS) indicates that the charge transfer impedance can be reduced roughly 2.5× when comparing 5% carbon black to ≤3% SWCNT conductive additive. Electrochemical cycling and rate testing demonstrate that SWCNT conductive additives provide significantly improved specific capacities (1100 mA h g−1 with 1% SWCNT) and rate performance (80% capacity retention at effective 1 C rate) over traditional carbon black conductive additives when using Ge-NP active material. In addition to the benefits for thermal stability, impedance, and rate performance, predicted energy density gains from Ge-NP anodes can be up to 20–25% in full batteries.