A Highly Efficient Sulfur Host Enabled by Nitrogen/Oxygen Dual‐Doped Honeycomb‐Like Carbon for Advanced Lithium–Sulfur Batteries

Abstract

High energy density and long cycle life of lithium–sulfur (Li–S) batteries suffer from the shuttle/expansion effect. Sufficient sulfur storage space, local fixation of polysulfides, and outstanding electrical conductivity are crucial for a robust cathode host. Herein, a modified template method is proposed to synthesize a highly regular and uniform nitrogen/oxygen dual‐doped honeycomb‐like carbon as sulfur host (N/O‐HC‐S). The unique structure not only offers physical entrapment for polysulfides (LiPSs) but also provides chemical adsorption and catalytic conversion sites of polysulfides. In addition, this structure offers enough space for loading sulfur, and a regular space of nanometer size can effectively prevent sulfur particles from accumulating. As expected, the as‐prepared N/O‐HC900‐S with high areal sulfur loading (7.4 mg cm−2) shows a high areal specific capacity of 7.35 mAh cm−2 at 0.2 C. Theoretical calculations also reveal that the strong chemical immobilization and catalytic conversion of LiPSs attributed to the spin density and charge distribution of carbon atoms will be influenced by the neighbor nitrogen/oxygen dopants. This structure that provides cooperative chemical adsorption, high lithium ions flux, and catalytic conversion for LiPSs can offer a new strategy for constructing a polysulfide confinement structure to achieve robust Li–S batteries.

Mo2N Quantum Dots Decorated N‐Doped Graphene Nanosheets as Dual‐Functional Interlayer for Dendrite‐Free and Shuttle‐Free Lithium‐Sulfur Batteries

“…Furthermore, the intractable "shuttling effect" derived from the intermediate lithium polysulfides (LiPSs) dissolved in the electrolyte also gives rise to grievous capacity degradation and low coulombic efficiency (CE). [9][10][11][12] Simultaneously, uncontrollable lithium-ion (Li + ) stripping-deposition and uneven distribution of Li + flux will lead to lithium dendrites growth and potential safety hazard, while the solid-electrolyte interface (SEI) film is formed and destructed repeatedly by the corrosion side effects of soluble LiPSs to lithium anode, which is about to cause the continuous consumption of electrolyte and lithium metal with the rapid decay of capacity. [13][14][15][16] Thus, it is highly desirable to design an advanced Li-S battery with a shuttling-inhibition cathode and dendrite-free anode configuration.…”

Sulfur Reduction Reaction in Lithium–Sulfur Batteries: Mechanisms, Catalysts, and Characterization

“…Dual doping or multiple doping would reveal more catalytic activities for SRR. [ 64–66 ] Peng et al. systematically investigated the SRR kinetics from an electrocatalytic point of view.…”

“…Dual doping or multiple doping would reveal more catalytic activities for SRR. [64][65][66] Peng et al systematically investigated the SRR kinetics from an electrocatalytic point of view. [16] As shown in Figure 5a, the initial reduction of sulfur to soluble polysulfides needed relatively low activation energies, implying an easy conversion process.…”

Construction of Ni/Ni3N heterojunctions as reversible micro-reaction centers for lithium polysulfides

“…The reasons mainly lie in the following two aspects. [3][4][5] On one hand, the high energy barrier of lithium polysulde (LiPS) transformation and the low electronic conductivity of sulfur generally lead to a large overpotential and slow reaction kinetics. On the other hand, the "shuttle effect" caused by soluble LiPSs results in the low utilization of active sulfur and poor reversible capacity.…”