Incorporation of HNb₃O₈ Nanosheets into PEDOT Aerogel with Enhanced Performance for Lithium-Ion Capacitor

Abstract

The development of anodes with fast electron and ion transport is indispensable for high-performance lithium-ion capacitors (LICs). In this work, we have successfully incorporated chemically exfoliated HNb3O8 nanosheets (E-HNb3O8) into PEDOT aerogel by electrostatic interactions between the negatively charged E-HNb3O8 and positively charged PEDOT:PSS through a facile hydrothermal method. The E-HNb3O8 nanosheets with shortened ion diffusion lengths offer numerous active sites, while the interconnected PEDOT skeleton offers continuous and conductive pathways for rapid electron and ion transport. Thereby, the PEDOT-E-HNb3O8 aerogel (PDT-Nb) exhibits large specific capacity (217 mAh g–1 at 0.1 A g–1), good rate capability (63 mAh g–1 at 1.0 A g–1), and decent cycling stability (153 mAh g–1 after 160 cycles at 0.1 A g–1). The LIC fabricated with PDT-Nb50 as the anode and activated carbon as the cathode provides a maximum energy density of 64 Wh kg–1, while retaining 66% capacity and almost 100% Coulombic efficiency over 5000 cycles at 1.0 A g–1. Our work demonstrates that the PEDOT-E-HNb3O8 aerogel holds great potential as an anode for the lithium-ion hybrid capacitor.