Nanoporous Graphene with Encapsulated Multicomponent Carbide as High-Performance Binder-Free Lithium-Ion Battery Anodes

Abstract

Metal carbides are considered attractive lithium-ion battery (LIB) anode materials. Their potential practical application, however, still needs nanostructure optimization to further enhance the Li-storage capacity, especially under large current densities. Herein, a nanoporous structured multi-metal carbide is designed, which is encapsulated in a 3D free-standing nanotubular graphene film (MnNiCoFe-MoC@NG). This free-standing composite anode with a high surface area not only provides more active Li⁺ storage sites but also effectively prevents the agglomeration or detachment of active material in traditional powder-based electrodes. Moreover, the free-standing design does not require additional binders, conductive agents, or even current collectors when used as LIB anode. As a result, the MnNiCoFe-MoC@NG anode exhibits a high specific capacity of 1129.2 mAh g⁻¹ at 2 A g⁻¹ and maintains a stable capacity of 512.9 mAh g⁻¹ after 2900 cycles of 5 A g⁻¹, which is higher than most reported Mo_xC-based anodes. Furthermore, the anode exhibits superb low-temperature performance at both 0 and −20 °C, especially at large current densities. These properties make the free-standing anode very promising in fast charging and low-temperature applications.