Niobium Diboride Nanoparticles Accelerating Polysulfide Conversion and Directing Li₂S Nucleation Enabled High Areal Capacity Lithium–Sulfur Batteries

Abstract

The shuttle effect of polysulfides and Li2S sluggish nucleation are the major problems hampering the further development of lithium–sulfur batteries. The reasonable design for sulfur host materials with catalytic function has been an effective strategy for promoting polysulfide conversion. Compared with other types of transition metal compounds, transition metal borides with high conductivity and catalytic capability are more suitable as sulfur host materials. Herein, a niobium diboride (NbB2) nanoparticle with abundant and high-efficiency catalytic sites has been synthesized by facile solid-phase reaction. The NbB2 with both high conductivity and catalytic nature could regulate 3D-nucleation and growth of Li2S, decrease the reaction energy barrier, and accelerate the transformation of polysulfides. Thus, the NbB2 cathode could retain a high capacity of 1014 mAh g–1 after 100 cycles. In addition, the high initial specific capacities of 703/609 mAh g–1 are also achieved at 5 C/10 C and could run for 1000/1300 cycles within a low decay rate of 0.057%/0.051%. Even with a high sulfur loading up to 16.5 mg cm–2, an initial areal capacity of 17 mAh cm–2 could be achieved at 0.1 C. This work demonstrates a successful method for enhancing the kinetics of polysulfide conversion and directing Li2S nucleation.

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

“…More importantly, the performance under high sulfur mass loading and lean electrolyte of pouch cells play a pivotal role in the practical applications of Li–S cells. [ 8,11 ] As presented in Figure 4i, the pouch cell with Mo 2 N@NG/PP reaches the areal capacity of 3.89 mA h cm –2 with 4.5 mg cm –2 sulfur loading and 6 µL mg –1 electrolyte/sulfur ratio under 0.2 C accompanied by two discernable voltage plateaus. Moreover, a high 3.01 mA h cm –2 reversibility was attained after 150 cycles, which demonstrates excellent stable cycling and great promise in practical Li–S 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.…”

Regulating Polysulfide Conversion Kinetics Using Tungsten Diboride as Additive For High‐Performance Li–S Battery

“…In addition, such polar substrates are semiconductive in nature which does not contribute effectively to the overall electronic conductivity of the cathode. However, when boride based materials, such as MgB 2 , [ 32 ] MoB 2 , [ 33 ] and NbB 2 [ 34 ] are used, the electron deficient property of boride ion leads to a consequence that the LiPS can interact efficiently through to B–S bond formation. Added to this, the borides possess an intrinsic metallic conductivity which can accelerate the LiPS conversion kinetics further ensuring a high utilization of trapped LiPS and minimize the shuttling effect.…”

Understanding the Catalytic Kinetics of Polysulfide Redox Reactions on Transition Metal Compounds in Li–S Batteries

“…(b) Cycling performance of NbB 2 /NPG/S cathodes. Reprinted with permission from ref . Copyright 2022 American Chemical Society.…”

“…The abovementioned advantages of metal borides have been used recently to demonstrate huge potential as polysulfide conversion promoters. Xu and his colleagues 165 synthesized the composites of N−P codoped graphene (NPG) with large specific surface area/excellent electrical conductivity and niobium diboride (NbB 2 ) nanoparticles with abundant and efficient catalytic sites. The NbB 2 nanoparticles could regulate the 3D nucleation and growth of Li 2 S, thereby guiding the radial growth of Li 2 S to balance the lateral diffusion of atoms (Figure 11a).…”