Transforming Coal Waste into Surface‐Engineered Carbons for Lithium–Sulfur Batteries

Slow redox kinetics and polysulfide shuttling hinder the practical deployment of lithium–sulfur (Li–S) batteries. Here, coal waste‐derived porous carbons with engineered surface chemistry and tailored textural properties as efficient sulfur hosts are demonstrated. Through oxygen and nitrogen doping via chemical and thermal treatments, it is shown that textural properties govern initial sulfur utilization while surface chemistry dictates long‐term cycling stability. Pristine coal waste porous carbon (CWPC) achieves the highest initial capacity (1114 mAh g −1 ) due to superior porosity, but suffered severe capacity fading (24% retention). Oxygen‐doped CWPC (CWPC‐O) demonstrates optimal performance by balancing adequate porosity with enhanced polysulfide confinement, delivering an initial capacity of 860 mAh g −1 and retaining 67% capacity after 100 cycles at 101 mA g −1 (0.2C). These findings highlight a sustainable pathway to transform coal waste into high‐value energy materials, offering both performance enhancement and environmental benefits for next‐generation Li–S batteries.