Bi‐Metallic Coupling‐Induced Electronic‐State Modulation of Metal Phosphides for Kinetics‐Enhanced and Dendrite‐Free Li–S Batteries

Abstract

Lithium-sulfur (Li-S) batteries are considered as next-generation promi sing batteries, yet suffer from severe capacity decay and low-rate capability. Transition metal compounds can solve these problems due to their unique electronic band structure, good chemical adsorption ability, and exceptional catalytic capability. Unraveling the essence of electronic states of metal compounds can fundamentally guide their structure design and promote Li-S battery performance. Herein, bi-metallic coupling-induced electronic-state modulation of metal phosphides is reported for kinetics-enhanced and dendrite-free Li-S batteries. Bimetallic phosphides nanoparticles-anchored N, P-co-doped porous carbons (NiCoP-NPPC) are facilely constructed via a laser-induced micro-explosion strategy. Theoretical calculations reveal that the electronic-state can be modulated via NiCo coupling, leading to lower polysulfides/Li + diffusion and conversion barriers. As a result, the assembled Li-S full cells based on NiCoP-NPPC exhibit greatly improved capacity (1150 mAh g -1 at 0.5 C) and cycle stability (84.3% capacity retention after 1000 cycles). Furthermore, they can be operated even under lean electrolyte (5.2 µL mg -1 ) with a high sulfur loading (6.9 mg cm -2 ), achieving a high areal capacity of 6.8 mAh cm -2 at 0.5 C. This study demonstrates that bi-metallic coupling-induced electronic-state modulation is an effective approach for developing high-performance Li-S batteries.

Understanding the Impact of Peripheral Substitution on the Activity of Co Phthalocyanine in Sulfur Reduction Catalysis

“…These together reveal that both CoTaPc and CoTnPc promote the redox conversion during reduction and oxidation. [25] The CoTnPc-C/S cell presents the smallest potential difference between the C2 and A peak (358 mV), further confirming the better catalytic effect of CoTnPc. [26] Tafel plots (Figure 2e) of the C2 peak in the cyclic voltammograms were obtained to better understand the liquid-solid SRR redox.…”

2D Nano‐Channeled Molybdenum Compounds for Accelerating Interfacial Polysulfides Catalysis in Li–S Battery

“…18 Clearly, 2D-MoN x demonstrated higher peak current and lower peak potential compared with 2D-MoO x and 2D-MoC x (Figure 5g and Figure S27, Supporting Information), indicating faster liquid-phase polysulfide conversion kinetics on 2D-MoN x . [46] The reversible Li 2 S nucleation and dissolution activities were revealed by potentiostatic tests. Based on Faraday's law, 2D-MoN x showed the most favorable Li 2 S nucleation capacity of 265.9 mAh g −1 compared to 2D-MoO x (177.6 mAh g −1 ), and 2D-MoC x (180.6 mAh g −1 ) (Figure 5h and Figure S28, Supporting Information).…”

Hybrid Ascharite/Reduced Graphene Oxide with Polysulfide Adsorption Host for Advanced Lithium–Sulfur Batteries

“…Recently, tremendous research has focused on modifying carbon materials by doping polar heteroatoms (Fe, B, N, O, or S) to improve the electrostatic attraction (Li bond) between the LPSs and doped carbon materials, which can effectively restrain the shuttling of LPSs. − Even so, the easy aggregation of S nanoparticles still easily leads to their migration and aggregation on nonpolar carbon surfaces, making it difficult to balance the high loading specific capacity and easy aggregation of S. Therefore, the effective limitation and simultaneous highly efficient conversion of sulfur species is a serious challenge for LSBs. As an alternative strategy to suppress the shuttling effect of LPSs, polar compounds or composites such as metal oxides, sulfides, , phosphides, , etc. have a strong affinity to LPSs and catalytically boost the conversion of LPSs to solid Li 2 S 2 /Li 2 S. Among them, metal oxides do not have a significant advantage as the optimal sulfur hosts due to their inherent insulating properties, that is, the extra diffusion step on the metal oxide surface requires extra energy.…”