Carbon microspheres built of La₂O₃ quantum dots-implanted nanorods: Superb hosts with ultra-long Li₂S_n-catalysis...

Practical utilization of Li-sulfur batteries (LSBs) is still hindered by the sulfur cathode side due to its inferior electrical conductivity, huge volume expansion and adverse polysulfide shuttling effects. Though using polar catalysts coupled with mesoporous carbons may well surmount these barriers, such unsheltered catalysts rarely survive due to oversaturated polysulfide adsorption and extra sulfuration side reactions. To overcome above constrains, we herein propose to implant highly reactive nanocatalysts into carbon matrix with few nanometers insertion depth for mechanical protection. As a paradigm study, we have embedded La₂O₃-quantum dots (QDs) into carbon nanorods, which are then assembled into carbon microspheres (CMs). As evaluated, La₂O₃ QDs-CMs can help elevate the cathode redox reaction kinetics and sulfur utilization ratios, delivering a large capacity of 1392 mAh g^-1 at 0.25C and high-capacity retention of 76% after total cycling. The thin carbon layers on La₂O₃ QDs exert a key role in impeding excess polysulfide accumulation on catalysts and thus prevent their deactivation/failure. Our strategy may guide a smart way to make catalysts-involved sulfur cathode systems with ultra-long working durability for LSBs applications.