Chlorine bridge bond-enabled binuclear copper complex for electrocatalyzing lithium–sulfur reactions

Lithium‐sulfur (Li–S) batteries are facing a multitude of challenges, mainly pertaining to the sluggish sulfur redox kinetics and rampant lithium dendrite growth on the cathode and anode side, respectively. In this sense, MXene has shown conspicuous advantages in serving as a dual‐functional promotor for Li–S batteries throughout the morphologic engineering, but still suffers from poor electrocatalytic activity and insufficient lithophilic sites. Herein, atomically dispersed Co sites are seeded onto the size effect‐enabled V2C MXene spheres (Co‐VC), leading to the generation of unique coordination configurations and rich active sites. Electrochemical tests combined with synchrotron radiation X‐ray 3D nano‐computed tomography and theoretical calculations unravel that Co‐VC with optimal coordination environments simultaneously boost sulfur reaction kinetics and lithium nucleation. As a consequence, Li–S batteries with Co‐VC modified separator can sustain a stable operation over 700 cycles with negligible capacity decay at 1.0 C, and delivers an areal capacity of 9.0 mAh cm−2 and desired cyclic performance at a high sulfur loading of 7.6 mg cm−2 with a lean electrolyte dosage of 4.0 µL mgS−1 at 0.1 C. The work opens a new avenue for boosting atomic‐scale site design with the aid of 2D substrates toward pragmatic Li–S batteries.

Seeding Co Atoms on Size Effect‐Enabled V₂C MXene for Kinetically Boosted Lithium–Sulfur Batteries

Song,

Sun,

Chen

et al. 2024

Atom‐Level 2D Catalysts Accelerating Deposition/Dissolution Kinetics in Lithium–Sulfur Batteries

Cheng,

Huang,

et al. 2024

The performance of high‐energy‐density lithium–sulfur (Li–S) batteries is limited by the unmanageable deposition/dissolution kinetics of lithium anode and sulfur cathode, leading to subpar electrochemical efficiency. Prior to being deposited on the electrolyte/electrode interface or within the interior, the solvated lithium‐ion (Li+) must undergo de‐solvation to produce free Li+ ions. These ions then participate in subsequent Redox reactions. The sulfur cathode faces challenges related to solid–liquid transformation and polysulfide conversion/shuttle, which impact the deposition/dissolution process. These issues collectively create insurmountable electrochemical barriers in lithium–sulfur batteries. Atom‐level 2D catalysts, contributing to the consummate atomic efficiency (≈100 at%), play an important role in accelerating deposition/dissolution kinetics in lithium–sulfur batteries. In the review, the preparation of atom‐level 2D catalysts and catalytic kinetic process on accelerating Li+ de‐solvation, Li0 stripping/dissolution, Li0 nucleation/deposition of lithium anode, polysulfide conversion, and LixS deposition of sulfur cathode are summarized, and the outlook of high‐performance single‐atom, multiple atoms modified 2D catalysts in lithium, sodium, and zinc‐based batteries is putting forward.

Phase Reconstruction‐Assisted Electron‐Li⁺ Reservoirs Enable High‐Performance Li‐S Battery Operation Across Wide Temperature Range

He,

Xiong,

Luo

et al. 2024

Lithium‐sulfur batteries (LSBs) are known as high energy density, but their performance deteriorates sharply under high/low‐temperature surroundings, due to the sluggish kinetics of sulfur redox conversion and Li+ transport. Herein, a catalytic strategy of phase reconstruction with abundant “electron‐Li+” reservoirs has been proposed to simultaneously regulate electron and Li+ exchange. As a demo, the 1T‐phase lithiation molybdenum disulfide grown on hollow carbon nitride (1T‐LixMoS2/HC3N4) is achieved via in situ electrochemical modulation, where the 1T‐LixMoS2 serves as an auxiliary “Li+ source” for facilitating Li+ transport and the HC3N4 acts as an electron donor for electronic supplier. From the theoretical calculations, experimental and post‐modern analyses, the relationship between the catalytic behaviors and mechanism of “electron‐Li+” reservoirs in accelerating the rate‐determining kinetics of sulfur species are deeply understood. Consequently, the cells with 1T‐LixMoS2/HC3N4/PP functional separator demonstrate excellent long‐term electrochemical performance and stabilize the areal capacity of 6 mAh cm−2 under 5.0 mg cm−2. Even exposed to robust surroundings from high (60 °C) to low (0 °C) temperatures, the optimized cells exhibit high‐capacity retention of 76.2% and 90.4% after 100 cycles, respectively, pointing out the potential application of catalysts with phase reconstruction‐assisted “electron‐Li+” reservoirs in LSBs.