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

Abstract

The practical application of Li–S batteries is severely limited due to low sulfur utilization, sluggish sulfur redox kinetics, intermediate polysulfide dissolution/shuttling, and subsequent anode degradation. A smart cathode with efficient electrocatalyst and a protected anode is necessary. Herein, hollow carbon (HC) spheres are used as a sulfur host to improve the electrical conductivity and buffer the volume expansion of active materials. Considering the weak interaction between carbon and lithium polysulfides (LiPS), tungsten diboride (WB2) nanoparticles are used as a conductive additive. Both experimental and density functional theory (DFT) comprehensively exhibit that metallic WB2 nanoparticles can firmly anchor the LiPS through B–S bond formation, accelerate their electrocatalytic conversion, and immobilize them. DFT also reveals that boron interacts with LiPS either through molecular or dissociative adsorption depending on its boron layer arrangement in WB2. Further, a freestanding lithiated‐poly(4‐styrene sulfonate) membrane constructed on lithium, offers a homogeneous Li‐ion flux, stable interface, and protection from LiPS. Finally, cells with the HC‐S+WB2 cathode and protected anode exhibit improved active material utilization, superior rate performance, and impressive cycling stability, even at high sulfur loading and less quantity of the electrolyte. Further, the pouch cells demonstrate high reversible capacity and an excellent capacity retention.

Decoration of defective graphene with MoS2enabling enhanced anchoring and catalytic conversion of polysulfides for lithium–sulfur batteries: a first-principles study

“…6(a). The calculation route of the sulfur reduction reaction refers to the previous report, [50][51][52][53][54] and our calculation results are basically consistent with the trend in these references: except that the last reduction step (Li 2 S 2 -Li 2 S) is an endothermic process, the rest of the elementary steps are exothermic, implying that the last reduction step is the rate-limiting step of the overall SRR. The endothermic reaction of the Li 2 S 2 -Li 2 S step is attributed to the intractable solid-state reaction, which is basically consistent with those reported in other literature reports.…”

Recent advances in modified commercial separators for lithium–sulfur batteries

“…The high polysulde rejection was attributed to the electrophilic boron centers in the COF that easily adsorbed the polysuldes. Work by Sahu et al 291 has also shown the efficacy of boron atoms as adsorptive centers for sulfur. Moreover, the small 1.2 nm pore sizes sieved the large polysuldes while allowing high Li diffusion.…”

Review and Perspectives of Electrochemical Energy Conversion and Storage in Metal Diborides and XBenes

“…AlB 2 -type metal borides are primarily ionic layered materials, where adjacent layers are held together by ionic bonding. , This structure gives rise to a number of interesting properties, including ultrahigh strength, good electrical and thermal conductivity, wear resistance, chemical inertness, and high melting point. , MgB 2 , the flagship member of the metal diboride family, is known for its superconductivity, TiB 2 is known for its use in ballistic armors, and AlB 2 has been used as a reinforcing material. ,− However, they are recently being revisited in multiple new domains due to their excellent electrochemical properties. One of the earliest reports highlighted the investigation of various metal diborides such as AlB 2 , CrB 2 , HfB 2 , MgB 2 , NbB 2 , TaB 2 , TiB 2 , VB 2 , and ZrB 2 as potential catalysts for HER, VB 2 and WB 2 for batteries, and MgB 2 for water splitting and lithium-ion batteries. ,,− Research trends in the synthesis of metal diborides encompass various methods including the solid-state reaction method, sol–gel synthesis, mechanical alloying, and self-propagating high-temperature synthesis (SHS). These techniques allow for precise control over material properties, microstructure, and phase composition, offering tailored metal diborides for specific applications.…”