A Ga-based liquid metal nanoparticles anode with carbon-coating layers for lithium-ion batteries

Abstract

Ga-based liquid metal has been reported as a self-healing anode for lithium-ion batteries due to their good fluidity and surface tension. However, the materials still face the challenge of poor long-term stability due to mutual fusion and volume expansion. In this work, the pristine liquid metal nanoparticles (LMNPs) are prepared by the ultrasonic stirring method. And then polydopamine-coated LMNPs (LMNPs@PDA) is obtained by the polymerization of dopamine. Finally, the carbon-coated LMNPs (LMNPs@C) are obtained by annealing under an Ar atmosphere. The carbon layer can efficiently alleviate the volume effect and prevent the mutual fusion of LMNPs@C maintaining its high specific surface area and capacity. The LMNPs@C anode achieves the initial capacity of 959.9 mAh g−1 and a discharge capacity of 452.1 mAh g−1 at 0.2 A g−1 after 100 cycles. Besides, under the current density of 5 A g−1, the LMNPs@C anode still maintains the discharge capacity of 185 mAh g−1. Moreover, the LMNPs@C anode maintains a low Rct and a high lithium-ion diffusion coefficient due to the carbon layer equipping good conductivity.