Chemical coupling of manganese–cobalt oxide and oxidized multi-walled carbon nanotubes for enhanced lithium storage

Abstract

Carbonaceous materials are extensively utilized to optimize the electrochemical performance of the transition metal oxides as anode for lithium-ion batteries. However, the in-depth mechanism of the synergistic effect and the interfacial interaction between transition metal oxides and conductive carbon material has not been elucidated clearly. Herein, by using the oxidized multi-walled carbon nanotubes (oMWCNTs), an advanced MnO2/(Co, Mn)(Co, Mn)2O4/oMWCNTs (MO/CMO/oMWCNTs) nanocomposite with abundant metal−oxygen−carbon (Me−OC) bonds as linkage bridge is fabricated for the first time. The strong covalent bonds interactions can simultaneously enhance the intrinsic sluggish kinetics and structural stability of MO/CMO/oMWCNTs nanocomposite. Meanwhile, the mixed transition metal oxides featuring mix valence state can significantly promote the electrode material activity. Consequently, the newly prepared MO/CMO/oMWCNTs electrode displays superior long-term durability with the capacity of 897 mAh g−1 over 1000 cycles at 2 A g−1 and ultrafast charging/discharging capability of 673 mAh g−1 at 5 A g−1. Detailed electrochemical kinetic analysis reveals that over 70% of the energy storage of MO/CMO/oMWCNTs electrode is dominated by the pseudocapacitive behavior. This work demonstrates an easily scalable approach for constructing high-performance transition metal oxides/carbon electrode materials through interfacial regulation.