Binary metal oxide anchored into dense N-doped CNTs arrays: Concerted pseudocapacitance and diffusion behavior for long-cyclic Li-ion half/full batteries

Electrode material is a crucial role to improve the performance of alkali metal ion batteries. Herein, a hierarchical nanosheet of binary metal oxide (ZnO/Co3O4) anchored into dense N-doped CNTs arrays (ZCO/NCNTs) was derived by two-step calcination. The design of ZCO/NCNTs containing binary metal oxides can better coordinate the pseudo-capacitance behavior of Co3O4 and the ion diffusion behavior of ZnO to realize a long-term stability for lithium storage at various current densities. Furthermore, the presence of slight Zn sources increases the catalytic efficiency of Co towards the growth of graphitized carbon during calcination process, resulting in the formation of dense carbon nanotubes for enhanced carrier transport. The strong interaction between the metal oxides and carbon nanotubes can accommodate the bulk expansion of electrode, obtaining high reversible capacity (-880 mAh g(-1)) and long cycle stability (>500 cycles). Thus, the full cell of LiFePO4 parallel to CZO/NCNTs at 0.3 A g(-1) exhibits excellent cycle stability with good retention rate after 200 cycles. This study provides a new basis for the improvement of lithium storage performance of metal oxide anode.