Na_0.76V₆O₁₅@Boron Carbonitride Nanotube Composites as Cathodes for High-Performance Lithium-Ion Capacitors

Abstract

Lithium-ion capacitors (LICs) are considered one of the most promising new-generation energy storage devices because they combine the advantages of lithium-ion batteries and supercapacitors. However, the widely used commercial carbon cathode greatly limits the electrochemical performance of existing LICs due to its limited specific capacity. Improving the specific capacity of the cathode is one of the keys to solving this problem. To this end, the Na0.76V6O15 (NaVO)@boron carbonitride nanotube (BCNNT) cathode has been successfully synthesized via a facile solid phase reaction and hydrothermal reaction followed by annealing. Benefitting from the synergy between the high conductivity of BCNNTs and the high capacity of NaVO, the NaVO@BCN cathode exhibits excellent capacity and good cyclic stability. A LIC was assembled by a prefabricated NaVO@BCN cathode and a prelithiated commercial hard carbon (HC) anode. Notably, the NaVO@BCN−1//HC LIC delivered an energy density of 238.7 Wh kg−1 at 200 W kg−1 and still delivered 81.9 Wh kg−1 even at 20 kW kg−1. Therefore, our strategy provides a novel idea for designing high-performance LICs.

Keywords

• Na_0.76V₆O₁₅@BCN nanotubes
• lithium-ion capacitors
• cathode
• capacitive behavior
• Faradaic behavior