Conformal convolution of grafted carbon nanotubes on graphene for the incorporation of lithiophilic Ag realizes dendrite-free and long-life lithium metal anodes

AbstractLithium metal battery anodes possess high specific capacity and low electrochemical potential. Nevertheless, the further advancement confronts challenges owing to an uncontrolled lithium dendrite growth and a severe volume variation. Herein, a conformally convolved architecture through the grafting of carbon nanotubes (CNTs) on graphene as a three-dimensional framework host and then the incorporation of lithiophilic Ag (Ag@CNTs/G) are proposed. The in-situ growth of CNTs on graphene matrix alleviates the volume variation. Based on the synergistic effect between Ag and the formed Li-Ag alloys, Li+ can diffuse preferentially into the bulk of the host, promoting the homogeneity and stability of Li deposition and effectively suppressing the lithium dendrite growth. The half cell exhibits a remarkably low nucleation overpotential of 16.7 mV at 0.5 mA cm−2. The symmetric cell demonstrates exceptional cycling stability over 1500 h at 1 mAh cm−2. The in-situ optical microscopy suggests the suppression of lithium dendrite growth in the Ag@CNTs/G. A full cell LiFePO₄||Ag@CNTs/G-Li delivers a stable capacity of 149.3 mAh g−1 and capacity retention of 96.2% for 500 cycles at 0.5C. The pouch cell can drive LED lights under various bending angles or repeated folding processes. The resulting Ag@CNTs/G-Li exhibits broad prospect in the field of energy storage.