From Flower-Like to Spherical Deposition: A GCNT Aerogel Scaffold for Fast-Charging Lithium Metal Batteries

Lithium metal anode has attracted the attention of both academic and industrial community for its high specific capacity and lowest redox potential. However, uncontrollable growth of lithium dendrite and low Coulombic efficiency (CE) exclude it from real world applications, especially in the fast-charging area. Herein, a graphene/carbon nanotube composite (GCNT) aerogel as a stable host for a lithium metal anode is proposed. The porous aerogel with large surface area and high conductivity can significantly decrease the local current density to enable spherical and uniform lithium deposition. The GCNT aerogel electrode can maintain a high CE of 97.7% for 430 cycles at a current of 1 mA cm⁻² under a capacity of 1 mAh cm⁻² while symmetric cells can sustain a high current up to 8 mA cm⁻². The composite anode paired with a LiFePO₄ cathode shows ultrahigh-rate capability of 18 C and ultrahigh capacity retention of 97.6% and average CE of 99.1% in the subsequent 570 cyclings at 4 C. When paired with the LiNi_0.8Co_0.1Mn_0.1O₂ cathode, the composite anode can also demonstrate a high rate of 10 C and achieve a high capacity retention of 83.2% and an average CE of 99.8% for the subsequent 470 cycles at 2 C.