High Sulfur Loading Cathodes Fabricated Using Peapodlike, Large Pore Volume Mesoporous Carbon for Lithium–Sulfur Battery

Abstract

Porous carbon materials with large pore volume are crucial in loading insulated sulfur with the purpose of achieving high performance for lithium-sulfur batteries. In our study, peapodlike mesoporous carbon with interconnected pore channels and large pore volume (4.69 cm(3) g(-1)) was synthesized and used as the matrix to fabricate carbon/sulfur (C/S) composite which served as attractive cathodes for lithium-sulfur batteries. Systematic investigation of the C/S composite reveals that the carbon matrix can hold a high but suitable sulfur loading of 84 wt %, which is beneficial for improving the bulk density in practical application. Such controllable sulfur-filling also effectively allows the volume expansion of active sulfur during Li(+) insertion. Moreover, the thin carbon walls (3-4 nm) of carbon matrix not only are able to shorten the pathway of Li(+) transfer and conduct electron to overcome the poor kinetics of sulfur cathode, but also are flexible to warrant structure stability. Importantly, the peapodlike carbon shell is beneficial to increase the electrical contact for improving electronic conductivity of active sulfur. Meanwhile, polymer modification with polypyrrole coating layer further restrains polysulfides dissolution and improves the cycle stability of carbon/sulfur composites.

Microporous bamboo biochar for lithium-sulfur batteries

“…Figure 5(a) shows the CV curves of the T_BC-S-50% electrode at a scan rate of 0.1 mV during the first three cycles. In the first cycle of the cathode reduction process, three peaks at approximately 2.3 V, 2.1 V, and 1.7 V are observed, which correspond to the reduction of elemental sulfur to higher-order lithium polysulphides (Li 2 S x , 4 < x < 8) and the reduction of higher-order lithium polysulphides to lower-order lithium polysulphides, or even to insoluble Li 2 S, respectively [31][32][33]. In the subsequent anodic scan, one asymmetric oxidation peak (which can be divided into two peaks) is observed at around 2.38 V and can be attributed to the conversion of lithium sulfides to lithium polysulfides and sulfur [31,34].…”

The Control and Effect of Pore Size Distribution in AEMFC Catalyst Layers

“…However, recent work has shed light on the physico-chemistry of anion-conducting membrane materials. [9][10][11] The adoption of steric and electronic protection of cationic groups, in addition to membrane reinforcements, are beginning to address the primary pathways of membrane degradation, 7,[12][13][14][15][16] and membranes possessing very high ion conductivity have recently been designed, 17 although less frequently have these strategies been combined and characterized in situ, in fuel cells. 18 Moreover, stabilized, doped, or grafted membrane materials are not amenable to serve as a soluble ionomer for use in the preparation of catalyst inks, and presently only two commercial products (FuMA-Tech FAA-3 and Tokuyama AS-4) are available for the purpose of forming catalyst layers for AEMFCs, which has greatly hindered the study and advancement of catalyst coated membranes for AEMFCs.…”

Synthesis and Alkaline Stability of Solubilized Anion Exchange Membrane Binders Based on Poly(phenylene oxide) Functionalized with Quaternary Ammonium Groups via a Hexyl Spacer

“…Common approaches to facilitate phase separation in AEMs are the concentration of ions into single units in statistical copolymers, 28,29 stiff side groups 30 or block copolymers. 20,[31][32][33][34] However, those approaches may lead to limitations in ion dissociation, and thus conductivity, because of the close proximity of the ions to the polymer structure. 28 The…”