Tandem Carbon Hollow Spheres with Tailored Inner Structure as Sulfur Immobilization for Superior Lithium–Sulfur Batteries

Abstract

The construction of lithium–sulfur battery cathode materials while simultaneously achieving high areal sulfur‐loading, adequate sulfur utilization, efficient polysulfides inhibition, rapid ion diffusion, etc. remains a major challenge. Herein, an internal regulatory strategy to fabricate the unique walnut‐like yolk–shell carbon flower@carbon nanospheres is presented (WSYCS) as sulfur hosts. The internal carbon flower, suitable cavity, and external carbon layer effectively disperse the insulate sulfur, accommodate volumetric expansion, and confine polysulfides, thus improving the performance of lithium–sulfur batteries. The finite element simulation method also deduces the enhanced Li+ diffusion and lithium–sulfur reaction kinetics. More importantly, WSYCS2 is grafted onto carbon fiber (CF) by electro‐spinning method to form a tandem WSYCS2@CF 3D film as a sulfur host for the free‐standing electrode. The corresponding battery exhibits an extremely high areal capacity of 15.5 mAh cm−2 with a sulfur loading of 13.4 mg cm−2. Particularly, the flexible lithium–sulfur pouch cell delivers a high capacity of 8.1 mAh cm−2 and excellent capacity retention of 65% over 800 cycles at a relatively high rate of 1C, corresponding to a calculated energy density of 539 Wh kg−1 and 591 Wh L−1. This work not only provides guidance for tailoring thick carbon/sulfur electrodes but also boosts the development of practical lithium–sulfur batteries.

Enhancing the Efficient Utilization of Li2S in Lithium–Sulfur Batteries via Functional Additive Diethyldiselenide

“…In addressing these challenges, researchers have undertaken persistent endeavors. These efforts encompass the design and synthesis of host materials with varied structures to physically confine polysulfides, − enhancing redox kinetics through the absorption and catalytic transformation of LiPSs using nitrides, , sulfides, − oxides, and other strategies. − Moreover, high-entropy compounds and quantum dots − have been introduced to enhance catalysis. Additionally, some researchers have successfully isolated LiPSs by alleviating their shuttle effect through separator modifications or functional interlayers. − These endeavors led to a notable enhancement in battery performance.…”