Improving the kinetics and surface stability of sodium manganese oxide cathode materials for sodium rechargeable batteries with Al2O3/MWCNT hybrid networks

摘要

We report the design and fabrication of a novel functional material in which protective Al2O3 nanoparticles are merged with highly conductive multi-walled carbon nanotubes (MWCNTs). In this paper, we discuss in detail the effects of the Al2O3/MWCNT hybrid networks on the electrochemical performance of sodium manganese oxide (Na0.44MnO2), which is used as an electrode material in sodium rechargeable batteries. The Al2O3/MWCNT hybrid networks, which are uniformly dispersed on the surface of Na0.44MnO2, change its surface bonding nature, resulting in an improvement in the cycling performance and rate capability of Na0.44MnO2. We ascribe these enhancements in performance to the inhibition of the formation of damaging NaF-based solid-electrolyte interface (SEI) layers during cycling, which enables facile transfer of Na ions through the Na0.44MnO2 electrode/electrolyte interface. Our findings regarding the control of the chemistry and bonding structure of the Na0.44MnO2 particle surfaces induced by the introduction of the Al2O3/MWCNT functional hybrid networks provide insight into the possibilities for achieving sodium rechargeable batteries with high power density and stability.