Going Beyond Lithium Hybrid Capacitors: Proposing a New High‐Performing Sodium Hybrid Capacitor System for Next‐Generation Hybrid Vehicles Made with Bio‐Inspired Activated Carbon

Abstract

A novel sodium hybrid capacitor (NHC) is constructed with an intercalation‐type sodium material [carbon coated‐Na3V2(PO4)3, C‐NVP] and high surface area‐activated carbon derived from an eco‐friendly resource cinnamon sticks (CDCs) in an organic electrolyte. This novel NHC possesses a combination of high energy and high power density, along with remarkable electrochemical stability. In addition, the C‐NVP/CDC system outperforms present, well‐established lithium hybrid capacitor systems in all areas, and can thus be added to the list of candidates for future electric vehicles. A careful optimization of mass balance between electrode materials enables the C‐NVP/CDC cell to exhibit extraordinary capacitance performance. This novel NHC produces an energy density of 118 Wh kg−1 at a specific power of 95 W kg−1 and retains an energy density of 60 Wh kg−1 with high specific power of 850 W kg−1. Furthermore, a discharge capacitance of 53 F g−1 is obtained from the C‐NVP/CDC cell at a 1 mA cm−2 current density, along with 95% capacitance retention, even after 10 000 cycles. The sluggish kinetics of the Na ion battery system is successfully overcome by developing a stable, high‐performing NHC system.