In Situ Construction of CeO₂-Incorporated Hybrid Covalent Organic Frameworks for Highly Efficient Lithium–Sulfur Batteries

Abstract

Lithium–sulfur (Li-S) batteries with high energy density, environmental friendliness, and low cost have still suffered from the short cycle life due to the shuttle effect of the dissoluble polysulfide intermediates. In this work, a hybrid host comprising ceric dioxide (CeO2) and covalent organic frameworks (COFs) was developed for the sulfur cathode. The hybrid host of CeO2/COFs manifests strong interaction with the polysulfide. Moreover, the polar interface of CeO2 and the highly 2D ordered structure of COFs endow good electrochemically catalytic activity, which accelerates the redox reaction and restrains the shuttle effect. Owing to the chemical and physical adsorption surface, the hybrid host of CeO2/COFs demonstrates a high initial capacity (1384 mAh g–1) and low decay rate (0.1%) at 0.5C. Collectively, the in situ hybrid strategy has high potential in elevating the performance of Li-S batteries.

Covalent Organic Framework Based Lithium–Sulfur Batteries: Materials, Interfaces, and Solid‐State Electrolytes

“…Numerous studies have focused on encapsulating S 8 in COFs with adequate pore architectures and polar functional sites to physically limit the domains of polysulfides or chemisorb polysulfides through the backbone, thereby diminishing the shuttle effect of polysulfides. [99][100][101][102][103][104][105] Most COF materials have poor intrinsic conductivity; therefore, appropriate carbon additives must be added to the cathode to compensate for the poor conductivity of COF/S composites. Reducing the carbon additive content and improving the conductivity of COF materials are important for improving the overall energy density of practical Li-S batteries.…”

Regulating Electrocatalytic Polysulfides Redox Kinetics through Manipulating Surface Electronic Structure of Molybdenum-Based Catalysts for High-Performance Lithium-Sulfur Batteries

“…Lithium-sulfur (Li-S) battery is the most promising candidate for high-efficiency energy storage devices due to the high theoretical specific capacity of the cathode (1672 mAh g –1 ) and energy density of about 2600 Wh kg –1 , as well as abundant resources and environment-friendly sulfur. − Unfortunately, the intrinsic insulative properties of sulfur and lithium sulfides (Li 2 S 2 /Li 2 S), large volume expansion (78%) of the cathode during the charge/discharge process, particularly the serious ″shuttle effect″ of soluble lithium polysulfides (LiPSs) mediators, and the sluggish solid–liquid–solid conversion kinetics of sulfur species make it impossible to guarantee its life span, which impedes the further development of Li-S batteries. − Using electrocatalysts has recently been mentioned as the most powerful strategy to fundamentally solve the intractable issues above. − They can effectively accelerate the electrocatalytic transformation and improve the electrochemical performance of Li-S batteries.…”