Mesoporous carbon film inlaid with Li3V2(PO4)3 nanoclusters through delaying sol-gel method for high performance lithium-ion hybrid supercapacitors

Abstract

A one-pot sol-gel method was modified through delaying gel curing by compositing Li3V2(PO4)3 with carbon. As a result, mesoporous carbon film inlaid with Li3V2(PO4)3 nanoclusters (named as LVP-C) was prepared to serve as cathode for the “non-consumable electrolyte type” and “internal serial hybrid type” Lithium-ion hybrid supercapacitor (LIHS). The LVP-C17 composite exhibited a considerably high initial discharge capacity of 128 mAh g−1 at 0.2C-rate, which was extremely close to the theoretical specific capacity. The BET specific surface area of the LVP-C17 composite is as high as 53.65 m2 g−1 and the Barret-Joyner-Halenda (BJH) pore-size-distribution curve displays that the pore sizes of the composite are mainly below 10 nm. The Raman test of the LVP-C17 composite mainly exhibits the graphitized carbon (SP2 hybridization) and a smaller R value (0.86), from which it can be inferred that the electronic conductivity of the composite is improved. The LIHS was designed by using LVP-C17 as cathode and active carbon (AC) as anode (LVP-C17//AC LIHS), which exhibited a higher energy density of 24 Wh kg−1 at a power density 405 W kg−1, with 77% specific capacitance retention after 1000 cycles in a wider voltage range of 0–2.7 V. Furthermore, even at higher power density of 2.03 kW kg−1, the energy density provided by the device can still retain 12.4 Wh kg−1. The device combines the electrochemical performance advantages of lithium-ion batteries (LIBs) with supercapacitors (SCs) and is comparable to the energy density and power density of currently commercially available Ni/MH batteries.