Realizing High Utilization of High-Mass-Loading Sulfur Cathode via Electrode Nanopore Regulation

Abstract

One main challenge of realizing high-energy-density lithium−sulfur batteries is low active materials utilization, excessive use of inert components, high electrolyte intake, and mechanical instability of high-mass-loading sulfur cathodes. Herein, chunky sulfur/graphene particle electrodes were designed, where active sulfur was confined in vertically aligned nanochannels (width ∼12 nm) of chunky graphenebased particles (∼70 μm) with N, O-containing groups. The short charge transport distance and low tortuosity enabled high utilization of active materials for high-mass-loading chunky sulfur/graphene particle electrodes. The intermediate polysulfide trapping effect by capillary effect and heteroatoms-containing groups, and a mechanically robust graphene framework, helped to realize stable electrode cycling. The as-designed electrode showed high areal capacity (10.9 mAh cm −2 ) and high sulfur utilization (72.4%) under the rigorous conditions of low electrolyte/active material ratio (∼2.5 μL mg −1 ) and high sulfur loading (9.0 mg cm −2 ), realizing high energy densities (520 Wh kg −1 , 1635 Wh L −1 ).

High-Tap-Density Sulfur Cathodes Made Beyond 400 °C for Lithium–Sulfur Cells with Balanced Gravimetric/Volumetric Energy Densities

“…In potentiostatic discharge testing (Figure c), their Li 2 S deposition-induced peak is present earlier and narrower; corresponding deposition capacity reaches 309.2 mAh g –1 , outperforming that of NiFe 2 O 4 QDs (122.4 mAh g –1 ) or N-rich carbon (94.6 mAh g –1 ). Above testing records and related kinetic analysis (the Avrami exponent and kinetic constant are fitted to 2.97 and 1.36 × 10 –14 , respectively; Figure S5) solidly affirm the faster Li 2 S n -to-Li 2 S conversion velocity and deposition rate for NiFe 2 O 4 QDs@N-rich carbon . According to integral areas under discharge profiles (Figure d), NiFe 2 O 4 QDs@N-rich carbon contributes the largest Li 2 S 8 /Li 2 S 6 and Li 2 S 6 /Li 2 S 4 reduction capacities of 22.3 and 23.3 mAh g –1 , respectively (while for NiFe 2 O 4 QDs and N-rich carbon, only 13.4/20.8 mAh g –1 and 4.1/22.6 mAh g –1 are achieved).…”

“…Above testing records and related kinetic analysis (the Avrami exponent and kinetic constant are fitted to 2.97 and 1.36 × 10 −14 , respectively; Figure S5) solidly affirm the faster Li 2 S n -to-Li 2 S conversion velocity and deposition rate for NiFe 2 O 4 QDs@N-rich carbon. 33 According to integral areas under discharge profiles (Figure 3d The in situ Raman spectroscopy is then used to explore the cathode changes in battery cycling (Figure 3e). The observed characteristic Raman peaks agree well with the data of S 8 , Li 2 S n , S 2 O 3 2− , and S x O 6 2− in literature.…”

Phosphate‐functionalized Zirconium Metal–Organic Frameworks for Enhancing Lithium–Sulfur Battery Cycling

“…High energy density is a crucial criterion for next‐generation Li−S batteries, which requires high mass loadings of active material and high areal capacity [55–58] . However, there is a trade‐off between cycling performance and sulfur loading.…”

Binary Metal Single Atom Electrocatalysts with Synergistic Catalytic Activity toward High‐Rate and High Areal‐Capacity Lithium–Sulfur Batteries

“…[ 13,14 ] However, Li–S batteries suffer from intricate issues, including the insulating nature of sulfur, the “shuttle effect” of polysulfides, and side reactions between Li metal and the electrolyte. [ 15–17 ] To promote the practical applications of Li–S batteries, the above challenges should be resolved to achieve acceptable electrochemical performance.…”