Lithium-sulfur (Li-S) batteries have attracted tremendous attention owing to their high theoretical energy density (~2600 Wh·kg-1), cost-effectiveness, and environmental benignity. However, the Li-S batteries usually have sluggish sulfur redox reaction kinetics, poor coulombic efficiency, and inferior electrochemical reversibility, which severely restrict their practical application.
Recently, Prof. Shouwu Guo's group at the School of Electronic, Information and Electrical Engineering of Shanghai Jiao Tong University published their research of improving the performance of Li-S batteries in Advanced Functional Materials, 2022, 2204635. (https://onlinelibrary.wiley.com/doi/10.1002/adfm.202204635)
In this work, a novel ultrasound-assisted photochemical reduction strategy has been developed to synthesize SA-regulated heterostructures of binary nanosheets. Benefiting from the heterointerface electronic interactions between Pt SAs/In2S3 and Ti3C2, the charge distribution at the interface can be induced, and the Pt SAs/In2S3/Ti3C2 heterostructure as a functional coating material can regulate homogeneous distribution of Li+ flux to inhibit the Li dendrite growth and show excellent electrocatalytic kinetic enhancement. Consequently, the Li//Li cells with the Pt SAs/In2S3/Ti3C2 separator exhibit an excellent stability during a continuous Li plating/striping process even at a high current density (5 mA·cm-2). In addition, the Li-S batteries using Pt SAs/In2S3/Ti3C2 separator deliver a superior rate performance, a specific capacity of 719.6 mAh·g-1 at 5 C, and long cycling stability with almost 100% CE. More importantly, even at a high sulfur areal loading of 6.4 mg·cm-2, and a low E/S ratio of 10 μL·mg-1, the initial areal capacity of Li-S pouch battery using Pt SAs/In2S3/Ti3C2 separator can still reach to 5.54 mAh·cm-2.
The authors envisage that the developed ultrasound-assisted photochemical reduction strategy might be general and useful for synthesizing SACs on 0D and 1D support matrices. This work can also provide a platform for developing various SA-based heterostructures functional separator for the next-generation high-performance flexible Li-S battery and even other energy storage devices.
This work was funded by the National Natural Science Foundation of China (61804156, and 62171275), and the China Postdoctoral Science Foundation (No. 2020M681300).
a) Schematic representation for the fabrication of SA-regulated heterostructure of binary nanosheets through an ultrasound-assisted photochemical reduction strategy. b) Schematic illustrations of polysulfides suppressing and Li anode deposition process on PP and heterostructures modified PP separator.
