Monodispersed FeS₂ Electrocatalyst Anchored to Nitrogen‐Doped Carbon Host for Lithium–Sulfur Batteries

Abstract

Despite their high theoretical energy density, lithium-sulfur (Li-S) batteries are hindered by practical challenges including sluggish conversion kinetics and shuttle effect of polysulfides. Here, a nitrogen-doped continuous porous carbon (CPC) host anchoring monodispersed sub-10 nm FeS 2 nanoclusters (CPC@FeS 2 ) is reported as an efficient catalytic matrix for sulfur cathode. This host shows strong adsorption of polysulfides, promising the inhibition of polysulfide shuttle and the promoted initial stage of catalytic conversion process. Moreover, fast lithium ion (Li-ion) diffusion and accelerated solid-solid conversion kinetics of Li 2 S 2 to Li 2 S on CPC@FeS 2 host guarantee boosted electrochemical kinetics for conversion process of sulfur species in Li-S cell, which gives a high utilization of sulfur under practical conditions of high loading and low electrolyte/sulfur (E/S) ratio. Therefore, the surfur cathode (S/CPC@FeS 2 ) delivers a high specific capacity of 1459 mAh g −1 at 0.1 C, a stable cycling over 900 cycles with ultralow fading rate of 0.043% per cycle, and an enhanced rate capability compared with cathode only using carbon host. Further demonstration of this cathode in Li-S pouch cell shows a practical energy density of 372 Wh kg −1 with a sulfur loading of 7.1 mg cm −2 and an E/S ratio of 4 µL mg −1 .

Advanced Nanostructured Materials for Electrocatalysis in Lithium–Sulfur Batteries

“…FeS 2 is also used as an electrocatalyst in Li-S batteries. Monodisperse sub-10 nm FeS 2 [ 115 ] nanoclusters were modified on porous carbon surfaces for enhanced electrochemical kinetics. FeS 2 accelerates the diffusion of ions and improves the solid–solid transformation kinetics ( Figure 9 e,f).…”

“…Reprinted from Ref. [ 115 ]. ( g ) Schematic diagram of Li 2 S catalytic oxidation on the surface of the material substrate.…”

A Polysulfide-Repulsive, In Situ Solidified Cathode–Electrolyte Interface for High-Performance Lithium–Sulfur Batteries

“…Lithium–sulfur battery, with a high theoretical specific energy of ca. 2600 Wh kg –1 , represents one of the cutting-edge electrochemical energy storage technologies for enabling long-driving-distance electric vehicles. − Currently, the electrochemical energy storage via the Li–S system is impeded by the inferior practical performance of the battery. − Formation and dissolution of Li polysulfide (LiPS) intermediates at the cathode–electrolyte interface (CEI) have been identified as two of the most notorious issues that hinder the stable operation of Li–S batteries. − During the discharge–charge process, the continuous loss of LiPSs from the S particle surface not only depletes active S on the cathode but also increases the salt concentration of the electrolyte and triggers unfavorable parasitic reactions with Li metal that passivate the anode. As a result, the Li–S batteries usually show significant capacity decay upon continuous cycling or raising the discharge–charge rate. − In addition to physically or chemically adsorbing the LiPSs by the cathode host, − solid electrolytes were also proposed to suppress LiPS formation and shuttling and to enable the stable operation of Li–S batteries. − However, most of the solid electrolytes show low bulk Li + conductivity and poor contact with the electrodes, which could hinder charge transfer and result in poor kinetics of the electrode reaction. , In situ creation of a partially solidified electrode–electrolyte interface (mostly the S-electrolyte interface) from one or more liquid electrolyte components has been proven effective in inhibiting LiPS shuttling while maintaining fast charge transfer owing to improved interfacial contact with the S cathode (Table S1).…”

Realization of a 594 Wh kg−1 Lithium‐Metal Battery Using a Lithium‐Free V2O5 Cathode with Enhanced Performances by Nanoarchitecturing

“…[ 11 ] For these reasons, some recent researches has been focused on the development of new types of LMA//high‐capacity Li‐free cathode batteries. [ 12–17 ] However, the unfavorable properties of conversion‐type cathode materials, such as the inevitable volume change and voltage hysteresis due to bond breaking/reconstruction and loss of sulfur during cycling, consequently cause fast capacity fading and finally cell failure. [ 18,19 ] Unlike conversion‐type lithium‐free cathodes, V 2 O 5 and MoO 3 show favorable lithium ion (Li + ) insertion/deinsertion, leading to high stability owing to their layered structures with van der Waals interactions between layers.…”

“…[11] For these reasons, some recent researches has been focused on the development of new types of LMA// high-capacity Li-free cathode batteries. [12][13][14][15][16][17] However, the unfavorable properties of conversion-type cathode materials, such as the inevitable volume change and voltage hysteresis due to bond breaking/reconstruction and loss of sulfur during cycling, consequently cause fast capacity fading and finally cell failure. [18,19] Unlike conversion-type lithium-free cathodes, V 2 O 5To realize a high-energy lithium metal battery (LMB) using a high-capacity Li-free cathode, in this work, nanoplate-stacked V 2 O 5 with dominantly exposed (010) facets and a relatively short [010] length is proposed to be used as a cathode.…”