Multi-ion Modulated Single-Step Synthesis of a Nanocarbon Embedded with a Defect-Rich Nanoparticle Catalyst for a High Loading Sulfur Cathode

Abstract

Oxygen defect-rich iron oxide (ODFO) nanoparticle catalyst on nanocarbon is in situ synthesized with the assistance of multi-ion modulation in one pot. The nanoparticle catalyst is employed to propel electrochemical kinetics in lithium/sulfur batteries. Electrochemical analysis and theoretical simulation evidently verify the critical role of defect sites on catalyzing conversion reactions of sulfur species and reducing energy barriers. As a consequence, the ODFO-enhanced sulfur cathode exhibits a high specific capacity of 1489 mA h g −1 at 0.1 C, an excellent rate performance of 644 mA h g −1 at 10 C, and a superior cycling stability with an average capacity fading rate of as low as 0.055% per cycle under an ultrahigh rate of 10 C. More importantly, even with a high sulfur loading of 11.02 mg cm −2 , the Li/S cell can still deliver an areal capacity of 8.7 mA h cm −2 at 0.5 C (9.23 mA cm −2 ). Such performance is the highest among reported metal oxide-catalyzed sulfur cathodes. This work opens a new route to boosting conversion reaction kinetics by introduction of active oxygen defect sites in electrodes of various emerging ultrafast batteries.

A Heterostructured Sulfonated CNT/Sulfur/CNT Cathode for Promoting the Binary Conversion of Polysulfides in Lithium‐Metal Batteries

“…The curve of the M/S/M-SO 3 Li electrode displays three pairs of highly reversible redox peaks at À 0.01/0.01 V (reduction of S to Li 2 S 6 and oxidation of Li 2 S to Li 2 S 2 ), À 0.19/0.19 V (reduction of L 2 S 6 to Li 2 S 2 and oxidation of Li 2 S 6 to S) and À 0.44/0.44 V (reduction of Li 2 S 2 to Li 2 S and oxidation of Li 2 S 2 to Li 2 S 6 ). [63,64] For the M/S/M electrode, these peaks appear at À 0.04/0.03, À 0.24/0.24 and À 0.58/0.56 V, thereby confirming the considerable improvement in the electrode stability and the immobilization and utilization of sulfur species. Moreover, the M/S/M-SO 3 Li electrode exhibits a significantly higher peak current, sharper peaks and smaller polarization than that of the M/S/M electrode.…”

Design a Catalytic Cathode Material with Abundant Oxygen Vacancies to Accelerate the Kinetics of Lean‐Electrolyte Lithium‐Sulfur Batteries

“…The catalytic activity is related to the concentration of OVs because the OVs as point defects can result in more sites for sulfur adsorption [25] and the OVs can promote the rupture of SÀ S bonding to expedite the reaction kinetics. [26] As shown in Figure 1, when the Ce content is greater than 0.4 wt%, the concentration of OVs doesn't increase with Ce increasing. The redundant Ce atoms may tend to aggregate, which may influence the catalytic effect of Ce-doped TiO 2 .…”

Advances and Prospects of 2D Graphene‐Based Materials/Hybrids for Lithium Metal–Sulfur Full Battery: From Intrinsic Property to Catalysis Modification

“…As the ever‐increasing requirement on high energy density, the high sulfur loading cathodes are needed for high areal capacity batteries, which tends to be restricted by the running out of adsorption sites on the matrix surface. Hybridization of metal atoms into the heteroatom‐doped graphene to form ultrahigh active catalytic matrix is able to boost the sulfur species conversion kinetics to clear off the saturation of adsorption sites, breaking through the adsorption limitation to achieve high areal capacity with scarcely sacrificing the energy density of batteries [13b,22b,24a,28] . During the entire process, the electronic density of the matrix is also significantly changed when metal/nonmetal heteroatoms are implanted into the pristine matrix, providing more sites for modulating the reaction/plating kinetics.…”

“…[ 20 ] Apart from pristine graphene, the graphene–derivatives such as with the addition of carbon nanotubes (CNTs) can provide porous structure or act as freestanding films with superb flexibility which are suitable for device and wearable technology application. [ 21 ] As far as we know, heteroatom doping and atomic catalyst modification are effective manners to realize the fine‐tuning of the physicochemical and electronic properties of 2D graphene‐based hybrids [11d,11e,13b,22] . The electronic density of the matrix is significantly changed when metal/nonmetal heteroatoms are implanted into the matrix, providing more sites for modulating the reaction/plating kinetics [19a,23] .…”