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

Abstract

Lithium−sulfur cells application is hindered by imbalanced gravimetric/ volumetric energy densities (E G /E V ) in pouch cells, owing to constraints in cathode engineering/compactness and Li 2 S n phase-conversion kinetics. By mimicking ternaryoxide cathodes, a synthetic route beyond 400 °C is proposed to make high-tap-density (maximum 2.12 g cm −3 ) microsphere cathodes, where sulfur and NiFe 2 O 4 quantum-dot catalysts are sealed in N-rich carbon shells. Conformal silica package proves critical to elevate cathode thermotolerant limit over sulfur sublimation temperature and block sulfuric vapor loss, enabling polymeric carbonization and high sulfur content retention (∼70.3%). The quantum dots and enclosed N-rich carbon help shorten the electrical resistance, anchor Li 2 S n molecules, and boost their phase conversions. Such cathodes exhibit high reversible capacities, great sulfur utilization, and cyclic behaviors. Packed pouch cells show balanced E G /E V and good bendability under high sulfur loading and lean-electrolyte conditions. Our strategy may offer new opportunities for other broad electrodes with low pack density and thermal instability challenges.

Suppression of long-chain lithium polysulfide formation through a selenium-doped linear sulfur copolymer cathode for high-performance lithium–organosulfur batteries

“…In the process of material synthesis and electrode fabrication, attaining high electrical conductivity and compacted density is essential for optimizing the performance of batteries and other energy storage systems. [36][37][38] This results in signicantly improved efficiency and overall effectiveness of energy storage devices. The electrical conductivity and compacted density of Se x S-TTCA with different Se/S mass ratios were measured and are represented in Fig.…”

Boosting Lean Electrolyte Lithium–Sulfur Battery Performance with Transition Metals: A Comprehensive Review

“…In 2023, the authors further encapsulated NiFe 2 O 4 quantum dots into nitrogen-rich carbon shells to make microsphere cathodes with high-tap-density (maximum 2.12 g cm −3 ). Such cathodes demonstrated high sulfur utilization and good cyclic behavior [173]. Guo's team constructed a multiple confined sulfur host by filling graphitized Pinus sylvestris with carbon nanotubes and defective LaNiO 3−x (LNO-V) nanoparticles (Fig.…”

Advanced engineering strategies for Li2S cathodes in lithium–sulfur batteries

“…49 Considering these challenges, 1D carbon materials present an advantageous solution. 110–112 They can be formed into free-standing structures and directly applied as Li 2 S cathodes, bypassing complex procedures. For example, Yu et al created ultrafine Li 2 S nanoparticles natively adorned within the conductive and porous network of interconnected N-doped carbon nanofiber (Li 2 S@NCNF).…”