Overcoming Cycling Limitations for High-Energy-Density Lithium-Ion Batteries

Project Overview

As technology continues to evolve at an exponential rate, there is a heightened demand to increase grid storage capacity. While lithium-ion batteries (LIBs) are one of the most promising clean energy alternatives to power handheld electronics and grid-size solutions, current technology falls short of meeting demands for higher energy storage capacity, especially in high-rate applications. Thanks to their high surface area and exceptional electronic conductivity, vertically-aligned single-walled carbon nanotubes (VA-SWCNTs) on metal foils promise to enable technological advancements to overcome capacity limitations in energy storage and enable stable, high-rate performance. In this work, we demonstrate growth of high-quality VA-SWCNTs on Inconel metal for use as a lithium-ion battery anode. Scale-up of SWCNT growth on Inconel foil to 100 cm2 exhibits nearly invariant CNT structural properties, even when synthesis is performed at near atmospheric pressure. SWCNT forests produced on large area metal substrates at close to atmospheric pressure possess a combination of structural features that are among the best demonstrated so far in the literature for growth on metal foils. Leveraging these achievements for energy applications, we demonstrate a VA-SWCNT LIB anode with capacity >1200 mAh/g at 1.0 °C, stable cycling beyond 300 cycles, and high-capacity retention at cycling up to 5.0 °C (12 min charge time). This robust synthesis and cycling behavior of high-quality VA-SWCNTs on metal foil are promising for mass production of energy storage devices with increased capacity and high-rate performance.

Mission Impact

This foundational work demonstrates growth of high-quality VA-SWCNTs on Inconel metal and their attractive high-capacity/ high-rate performance when used as a LIB anode. Overall, this study provides a valuable framework to develop high energy density batteries with long cycle life to power the future of the energy grid, and thus addresses DOE's energy and environmental security missions. This work is closely aligned with the LLNL Mission Focus Area of "Energy Security and Climate Resilience" and Director's Initiatives "Accelerated Materials and Manufacturing - optimal design and advanced manufacturing processes."