Nb2O5 nanoparticles encapsulated in ordered mesoporous carbon matrix as advanced anode materials for Li ion capacitors

Abstract

Lithium ion capacitors (LICs), which have high energy density and power density and benefit from the combination of the merits of batteries and supercapacitors, have been attracted tremendous attention. The sluggish faradaic battery anode is a big challenge for the development of high-performance LICs. In this study, an Nb₂O₅/ordered mesoporous carbon (CMK-3) nanocomposite has been synthesized via the nanocasting technology using CMK-3 as the hard template and NbCl₅ as the precursor. The Nb₂O₅/CMK-3 electrode exhibits significantly enhanced electrochemical performance in terms of specific capacity, rate capability and cyclic stability when compared with bulk Nb₂O₅. Furthermore, a high performance LIC composed of the Nb₂O₅/CMK-3 nanocomposite as the anode and activated carbon derived from peanut shell as the cathode was constructed, which exhibits a high energy density of 43.9 W h kg⁻¹ (at a power density of 87.5 W kg⁻¹) and high power density of 8750 W kg⁻¹ (at an energy density of 24.4 W h kg⁻¹). Such outstanding performance mainly stems from the synergic effects between the mesoporous carbon matrices and the well-dispersed active material nanoparticles, which increase electronic conductivity and the reactivity of Nb₂O₅.