Holey Graphene/Sulfur Composite Cathodes Via Coupling with Ferroelectric Nanoparticles for Sustainable and High-Capacity Lithium-Sulfur Batteries

Abstract

Lithium-Sulfur (Li-S) batteries have been considered promising for high energy density batteries to be used in electronic devices, electric vehicles (EV) and aircrafts which are becoming more prevalent. In addition, Li-S batteries have high theoretical capacity of 1,675 mAh/g in comparison to LIBs of 300 mAh/g. Although Li-S batteries are in great demand, their development is still plagued by rapid capacity fading mainly stemming from polysulfide shuttle. To improve the electrochemical performance of the cathode in Li-S batteries, holey graphene (hG) and carbon-based materials are employed. Holey graphene (HG) contains conductive skeletons as electron transfer paths and abundant mesoporous for longitudinal transport of ions. This architecture ensures efficient charge delivery throughout a thick electrode and maximizes electrode utilization, achieving high-rate and high-capacity energy storage. The coupling of a highly polarized ferroelectric nanoparticles materials (FNPs) layer is an approach that can be used to reduce the characteristic polysulfide shuttling in Li-S batteries. This coupling helps to build up an internal electric field and induces macroscopic charge separations on the surface of the cathode of Li-S batteries. The dry compression manufacturing process facilitates bonding between Sulfur and ferroelectric nanoparticles to generate a more stable cathode. In the present report we are presenting preliminary results of cathode having composition S47.5(FNPs)5hG47.5 in terms of structure, surface morphology and electrochemical performance. A reversible capacity of ~1,400 mAh/gs has been achieved with high coulombic efficiencies (> 87%) and low-capacity fading rate of 0.016% per cycle upto 60 cycles. The active sulfur mass loading ranging from 5.72 mgs/cm2 to 7.01 mgs/cm2 allows maximum high areal capacity up to ~10 mAh/cm2 and superior rate capability for 0.2mA/cm2 and 0.5 mA/cm2. These results suggest sustainable and high-yielding Li–S batteries can be obtained for potential commercial applications.