Tuning the d-Band Center via High-Entropy-Induced Lattice Strain Enables Reversible Nanosheet-like Li2O2...

The reversible formation/decomposition of Li2O2 is central to nonaqueous lithium-oxygen (Li-O2) batteries, where sluggish oxygen redox kinetics causes large polarization and limited capacity, undermining their otherwise high theoretical energy density. Here, a high-entropy sulfide catalyst ((CoFeNiMnZn)3S4) is fabricated via a multistep low-temperature strategy. The high-entropy-induced lattice strain regulates the electronic structure and d-band center of the catalyst, thereby optimizing the adsorption behavior of intermediates. Unlike the film- or toroid-like discharge products observed on quaternary catalyst cathodes, nanosheet-like Li2O2 is generated on the (CoFeNiMnZn)3S4 cathode, promoting highly reversible discharge-recharge processes. When employed as cathodes in Li-O2 batteries, the (CoFeNiMnZn)3S4 delivers superior electrochemical performance, including a high discharge capacity (17874 mAh g-1), a low overpotential of 0.57 V, and enhanced cycling stability (over 420 cycles at 1000 mA g-1). This work establishes a new paradigm for designing high-entropy sulfide electrocatalysts toward high-performance Li-O2 batteries.