Lithium-O2/CO2 battery has been recently
developed due to its higher capacity than Li–O2 battery
and high impact on energy and environmental problems. Ionogels composed
of ionic liquid ([bmim][Tf2N], [bmim][PF6] or
[bmim][I]), and poly(vinylidene fluoride) (PVDF) is applied as a binder
of carbon particles on cathode of Li–O2/CO2 battery. A porous carbon cathode with ionogel binder was fabricated
by drying and impregnation techniques in supercritical carbon dioxide
at 40 °C and 20.0 MPa. The effect of ionic liquid on cathode
properties was investigated by various ratios of ionic liquid amount
in the ionogel binder. The porous carbon cathodes were further used
to test the discharge capacity of Li–O2/CO2 batteries. We found that the capacity of battery was enhanced as
the amount of ionic liquid in the gel binder increased, while the
cathode with PVDF–[bmim][Tf2N] ionogel binder had
the highest discharge capacity at 15.07 mAh cm–2. The mechanism of capacity enhancement relies on the reduction of
interfacial resistance between electrolyte and cathode and the improvement
of reaction gases solubilities into the ionogel binder on the porous
carbon cathode.
The present study investigates porous carbon black aerogels fabricated with polyvinylidene uoride (PVDF) as binder and N-methylpyrrolidone (NMP) as solvent and dispersant, and dried by supercritical drying using CO 2 at 20 MPa and 40°C, which resulted in greater porosity and thickness than aerogels prepared by evaporative drying. Increasing the ratio of solvent in carbon black slurry increased the porosity and thickness and decreased electrical conductivity. The electrical conductivity of aerogels prepared at 60°C is higher than aerogels prepared at 40°C. However, aerogels prepared at 80°C are broken because evaporative drying occurred simultaneously, whereby the conductivity reduced. Porous carbon nano ber aerogel made by supercritical drying using CO 2 at 20 MPa and 40°C had porosity as high as carbon black aerogel. However, its electrical conductivity is less than carbon black aerogel because of the net-like structure which has less touch points between the bers compared to carbon black particles which gather together and have more touch points between the particles. A coin cell consisting of porous carbon nano ber aerogel or electrode, lithium and electrolyte was connected with oxygen and carbon dioxide at the ratio of 1 : 1. Regardless of its low electrical conductivity, the carbon nano ber electrode showed superior electrical capacity. It also withstood 10 cycles, whereas the carbon black electrode could not withstand 10 cycles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.