Co/CoS₂ Heterojunction Embedded in N, S‐Doped Hollow Nanocage for Enhanced Polysulfides Conversion in High‐Performance Lithium–Sulfur Batteries

Abstract

Modulating the electronic configuration of the substrate to achieve the optimal chemisorption toward polysulfides (LiPSs) for boosting polysulfide conversion is a promising way to the efficient Li–S batteries but filled with challenges. Herein, a Co/CoS2 heterostructure is elaborately built to tuning d‐orbital electronic structure of CoS2 for a high‐performance electrocatalyst. Theoretical simulations first evidence that Co metal as the electron donator can form a built‐in electric field with CoS2 and downshift the d‐band center, leading to the well‐optimized adsorption strength for lithium polysulfides on CoS2, thus contributing a favorable way for expediting the redox reaction kinetics of LiPSs. As verification of prediction, a Co/CoS2 heterostructure implanted in porous hollow N, S co‐doped carbon nanocage (Co/CoS2@NSC) is designed to realize the electronic configuration regulation and promote the electrochemical performance. Consequently, the batteries assembled with Co/CoS2@NSC cathode display an outstanding specific capacity and an admirable cycling property as well as a salient property of 8.25 mAh cm−2 under 8.18 mg cm−2. The DFT calculation also reveals the synergistic effect of N, S co‐doping for enhancing polysulfide adsorption as well as the detriment of excessive sulfur doping.

Exquisitely constructing hierarchical carbon nanoarchitectures decorated with sulfides for high-performance Li–S batteries

“…26,27 Zeolitic imidazolate framework-67 (ZIF-67), which is composed of metal ions (Co 2+ ) and an organic compound (2-methylimidazole), is a popular type of MOF. 28 In recent years, ZIF-67 derived carbon materials 29 with Co-based compounds, such as elemental cobalt, 30,31 cobalt oxide, 32,33 cobalt sulfide, 34,35 and cobalt selenide, 36,37 have been widely used as sulfur host materials and separator modifiers for LSBs. They not only have a strong chemical adsorption to LiPSs but also effectively accelerate the kinetics of the LiPS reaction process, so as to improve the electrochemical performance of LSBs.…”

High-Entropy Metal Oxide-Coated Carbon Cloth as Catalysts for Long-Life Li–S Batteries

“…To address the above problems, considerable efforts are proposed. One of the most popular strategies is incorporating sulfur into the carbon matrix, which provides a highly conductive pathway for rapid electron/lithium-ion transport as well as effective interaction with lithium polysulfides (LiPSs). − However, owing to the weak affinity between the polar LiPSs and nonpolar carbon material, the capture ability for LiPSs is not enough, which cannot acquire a stable sulfur electrode. , Recently, researchers have found that polar metal oxides can be beneficial for anchoring the LiPSs by chemical immobilization. Compared with single metal oxides, multicomponent metal oxides such as ZnCo 2 O 4 and NiFe 2 O 4 are confirmed as more effective catalytic centers owing to the synergistic effects of the different metal ions. , In terms of the contribution of multicomponent metal oxides, a new class of high-entropy oxides (HEO) with the features of single-phase and entropy-stabilized crystalline comes into being.…”