A lithiophilic carbon scroll as a Li metal host with low tortuosity design and “Dead Li” self-cleaning capability

Abstract

On the way to achieve a practical lithium (Li) metal anode for next-generation batteries, the formation and accumulation of inactive “Dead Li” is an unavoidable issue. The accumulation of “Dead Li” leads to increased internal mass-transfer resistance which seriously deteriorates the performance of Li metal batteries during long-term cycling. In this study, by accommodating Li metal into a copper oxide coated carbon scroll host with a vertically aligned framework which possesses a unique low-tortuosity structure, the cycling stability of the Li anode can be significantly improved. It is demonstrated that the mass-transfer resistance and the concentration polarization near the Li metal surface can be greatly alleviated by using this low-tortuosity anode structure design. “Dead Li” that is formed on the electrode surface can automatically fall into the inner tunnel of the carbon host, endowing the anode with the capability of “Dead Li” self-cleaning. As a result, our new Li electrode can remain electrochemically active even after 1000 h in a symmetric cell measurement from 1 mA cm⁻² to 1 mA h for 500 cycles. The as-reported structure design of the Li anode in this work is compatible with most of the modification technologies that have been applied to conventional Li foil electrodes, providing this new Li anode with a great potential to be applied in subsequent Li anode studies.