Multifunctional surface-engineering of 3D-lithiophilic nanocarbon scaffold for high-voltage anode-minimized lithium metal batteries

초록

A lithium metal anode (LMA) offers the lowest negative potential and a high specific/volumetric capacity; however, it promotes the decomposition of electrolyte and leads to poor Coulombic efficiency, particularly in a conventional carbonate-based electrolyte which is electrochemically stable at high voltage; >4 V (vs Li+/Li). Herein, we report the development of a catalytic support to realize a high-performance LMA, suitable for use in carbonate-based electrolyte systems, consisting of a 3D carbon nanofiber scaffold (3D-CNS) coated with LiNO3. The lithium-rich inorganic coating preferentially decomposes on the surface of the 3D-CNS during initial lith-iation, forming an inorganic compound-rich, solid-electrolyte interface (SEI) layer before any electrolyte de-composes. The LiNO3-derived SEI layer not only inhibits side reactions that consume electrolyte but also improves lithium-ion transport kinetics, leading to LMAs with high CE and superior rate capability. In addition, residual LiNO3 promotes the uniform deposition/dissolution of lithium during cycling, facilitating stable cycling over 300 cycles. Moreover, a lithium metal battery featuring a high-voltage NCM811 cathode and a LMA based on the proposed support with minimal excess lithium loading demonstrates significantly improved cycling performance with high energy and power densities of -570 Wh kg-1 and -690 W kg-1, respectively.

키워드