Phase Engineering of 2D Telluride Crystals for Sulfur Catalysis in Batteries

Abstract The kinetics difference of sulfur reduction reaction (SRR) results in the “shuttle effect” issue in lithium–sulfur (Li–S) batteries, challenging their commercial use. The electrocatalytic polysulfide conversion is regarded as a proactive strategy for suppressing such shuttling. Here, a phase engineering strategy is proposed for constructing high‐performance crystal catalysts, using 2D TaTe 2 as a typical example to demonstrate a rational catalyst design principle that is in urgent need of developing the right catalyst to push forward the practical use of Li–S batteries. The Te‐enriched crystal edges of 2D TaTe 2 facilitate the formation of thin‐layer LiTe x analogs, thereby accelerating the rate‐determining step in SRR, as evidenced by a reduction in activation energy from 0.96 to 0.76 eV. The presence of dynamic catalytic intermediates (LiTe x ) and the mitigation of the shuttle effect are confirmed through in situ Raman spectroscopy. Consequently, the TaTe 2 ‐catalyzed Li–S battery delivers an outstanding cycle‐ability with a low capacity degradation rate of 0.035% per cycle over 1500 cycles at 2.0 C, and even an ultrahigh capacity retention of 94.9% over 100 cycles is achieved for a pouch cell with a high areal sulfur loading ≈9.4 mg cm −2 .