Polyaniline-Encapsulated Hollow Co–Fe Prussian Blue Analogue Nanocubes Modified on a Polypropylene Separator To Improve the Performance of Lithium–Sulfur Batteries

Abstract

Recent studies of lithium–sulfur (Li–S) batteries have identified that a modified separator plays a critical role in challenging the capacity fading and shuttle effect of lithium polysulfides (LiPSs). Herein, we report a polyaniline-encapsulated hollow Co–Fe Prussian blue analogue (CFP@PANI) for separator modification. The open frame-like hollow CFP was synthesized via oriented attachment (OA). To improve the catalytic effect and electrical conductivity, PANI was coated on the synthesized CFP. The resulting CFP@PANI was applied on the conventional polypropylene (PP) separator (CFP@PANI-PP) with vacuum filtration. With a ketjen black/sulfur (KB/S) cathode with 66% of the sulfur load, the CFP@PANI-PP exhibited an initial capacity of 723.1 mAh g–1 at a current density of 1 A g–1. Furthermore, the CFP@PANI-PP showed stable cycling performance with 83.5% capacity retention after 100 cycles at 1 A g–1. During the 100 cycles, each cycle maintained high coulombic efficiency above 99.5%, which indicates that the CFP@PANI-PP could inhibit LiPS migration to the anode side without a Li+ transport disturbance across the separator. Overall, the CFP@PANI-PP efficiently suppressed LiPSs, resulting in enhanced electrochemical performance. The current study provides useful insight into designing a nanostructure for separator modification of Li–S batteries.

Polyaniline-Coated Porous Vanadium Nitride Microrods for Enhanced Performance of a Lithium–Sulfur Battery

“…Table S1 lists the cyclic performance of some sulfur hosts for Li-S battery. The cyclic performance of VN/S@PANI was superior to those of the VN/S microflowers [ 11 ], PANI@BDC/S [ 35 ], S/VN@CNFs [ 38 ], VN-NCNFs/S nanofibers [ 39 ], V 2 O 3 -VN@NC/S [ 40 ], and some other vanadium-based composites [ 41 , 42 , 43 , 44 ]. In Figure 7 e, VN/S@PANI cathode delivered 338.6 mAh g −1 after 500 cycles at 50 °C, and the Coulombic efficiency remained at 99.9%.…”

The Inducement and “Rejuvenation” of Li Dendrites by Space Confinement and Positive Fe/Co‐Sites

“…[ 42 ] As for Fe 2p (Figure S5, Supporting Information), the H‐PBA has four peaks at 708.5 (Fe 2+ 2p 3/2 ), 710.2 (Fe 3+ 2p 3/2 ), 721.2 (Fe 2+ 2p 1/2 ), and 723.5 eV (Fe 3+ 2p 1/2 ), while the S‐PBA only shows Fe 2+ peaks. [ 43 ] Since the sodium citrate with strong reducing ability can reduce Fe 3+ to Fe 2+ to form S‐PBA within 10 min, while partial Fe 2+ transform to Fe 3+ after 360 min to obtain H‐PBA. As further verified by the Fourier transform infrared spectroscopy (FT‐IR), both H‐PBA and S‐PBA exhibit identical characteristics, where the peak located at 2083.87 cm −1 is attributed to the characteristic stretching vibration of −CN in Co 2+ −NC−Fe 2+ (Figure S6, Supporting Information).…”

Recent advances in modified commercial separators for lithium–sulfur batteries

“…This was due to the improved reaction kinetics and sulfur utilization because of the signicantly lower charge transfer resistance with PANI. Jo et al 183 found similar improvements to initial capacity and cyclability aer coating Co-Fe Prussian Blue analogs (CFPs) with PANI and applying the PANI/CFP to a standard Celgard membrane. The PANI coating on the CFPs allowed more effective binding with the PVDF and NMP binder solution, yielding a more structurally stable surface modication on the PP substrate.…”