Lithiophilic-lithiophobic gradient electrode for dendrite-suppressed lithium metal anodes

초록

The increasing demand for high-energy-density batteries has positioned lithium (Li) metal as a promising next-generation anode material owing to its potential to deliver significantly higher energy density than conventional anodes. However, its practical application is limited by uncontrolled dendrite formation and pronounced volume fluctuations during cycling. Here, we design a lithiophilic-lithiophobic gradient host (SnO2/NPG-G) that effectively regulates Li nucleation and deposition. The host comprises a lithiophilic bottom layer of spherical SnO2/ nanoperforated graphene (NPG), which promotes uniform nucleation through abundant carbonyl groups and nanopores, and a lithiophobic top layer of single-walled carbon nanotubes (SWCNTs), which suppresses dendritic propagation at the electrode surface. This gradient architecture enables stable Li plating/stripping in symmetric cells for over 1350 h at 1 mA cm-2 with low overpotential and maintains a similarly low overpotential even at a high current density of 10 mA cm-2. Furthermore, a uniform and dendrite-suppressed Li morphology is preserved even at a high areal capacity of 6 mAh cm-2, as confirmed by morphological analysis after Li deposition behavior evaluation. The SnO2/NPG-G-Li||LiFePO4 full cell demonstrates outstanding cycling stability with 92 % capacity retention after 400 cycles. These findings highlight the efficacy of the proposed gradient host design in effectively enabling high-performance Li metal batteries.

키워드