Commercial LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an Efficient Bifunctional Separator Modifier for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have garnered significant interest as the next‐generation energy storage systems, owing to their high theoretical specific capacity and cost efficiency. However, their commercialization is severely limited by the notorious shuttle effect of soluble lithium polysulfides (LiPSs) and sluggish redox kinetics. Herein, we report a scalable approach to mitigate these issues by developing a functional separator modified with commercial LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) combined with Super P (SP) conductive carbon. The NCM523 acts as both a strong chemisorbent and electrocatalyst, offering effective anchoring of LiPSs and accelerating the conversion between long‐chain polysulfides and Li 2 S. Concurrently, the incorporated SP carbon ensures improved electrical conductivity and facilitates charge transfer. As a result, the Li–S battery equipped with the NCM523‐SP modified separator achieves a high initial discharge capacity of 1295.6 mAh g −1 at 0.1 C and a low capacity decay rate of 0.09% per cycle over 500 cycles at 0.5 C. Furthermore, the modified battery exhibits a rate capability of 621.6 mAh g −1 at 3.0 C, along with self‐discharge behavior with only 6.1% capacity decay over 3 days. This work highlights the practical potential of commercial layered oxides as separator modifiers for high‐performance Li–S batteries.