Hierarchical nanoarchitectured hybrid electrodes based on ultrathin MoSe2 nanosheets on 3D ordered macroporous carbon frameworks for high-performance sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) have been considered a promising alternative to lithium-ion batteries for large-scale stationary energy storage due to their low cost and the abundant resources of sodium. Nevertheless, the lack of anodes with high capacity and long-term cycling stability seriously hinders the commercialization of SIBs. Herein, ultrathin 2D MoSe₂ nanosheets (∼2 nm) strongly bonded on 3D ordered macroporous (3DOM) carbon are designed to greatly improve sodium storage. The resulting MoSe₂@C composite delivers high capacity (410 mA h g⁻¹ at 0.5 A g⁻¹ after 100 cycles, considering the total weight of the active MoSe₂@C), superior rate capability (279 mA h g⁻¹ at 10 A g⁻¹), and long-term cycling stability (384 mA h g⁻¹ at 5 A g⁻¹ after 2000 cycles). The enhanced electrochemical performance can be ascribed to synergistic effects between the hybrid structures constructed from 2D MoSe₂ nanosheets and the 3DOM carbon architecture, which can provide expanded interlayer spacing (0.76 nm for a single layer) facilitating Na⁺ insertion/extraction, strong electronic coupling of Mo–C boosting the fast electron/ion transfer, and ordered 3D cavities accommodating the volume expansion and preventing the stacking of MoSe₂ nanosheets upon cycling.