Tubular CoFeP@CN as a Mott–Schottky Catalyst with Multiple Adsorption Sites for Robust Lithium−Sulfur Batteries. Issue 24 (8th May 2021)

• Record Type: Journal Article
• Authors: Zhang, Chaoqi; Du, Ruifeng; Biendicho, Jordi Jacas; Yi, Mingjie; Xiao, Ke; Yang, Dawei; Zhang, Ting; Wang, Xiang; Arbiol, Jordi; Llorca, Jordi; Zhou, Yingtang; Morante, Joan Ramon; Cabot, Andreu
• Is Part Of: Advanced energy materials. Volume 11:Issue 24(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-08
• Subjects: carbon nitrides -- lithium–sulfur batteries -- metal phosphides -- Mott–Schottky heterostructure -- polysulfides -- shuttle effect; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202100432
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: The shuttle effect and the sluggish reaction kinetics of lithium polysulfide (LiPS) seriously compromise the performance of lithium–sulfur batteries (LSBs). To overcome these limitations and enable the fabrication of robust LSBs, here the use of a Mott–Schottky catalyst based on bimetallic phosphide CoFeP nanocrystals supported on carbon nitride tubular nanostructures as sulfur hosts is proposed. Theoretical calculations and experimental data confirm that CoFeP@CN composites are characterized by a suitable electronic structure and charge rearrangement that allows them to act as a Mott–Schottky catalyst to accelerate LiPS conversion. In addition, the tubular geometry of CoFeP@CN composites facilitates the diffusion of Li ions, accommodates volume change during the reaction, and offers abundant lithiophilic/sulfiphilic sites to effectively trap soluble LiPS. Therefore, S@CoFeP@CN electrodes deliver a superior rate performance of 630 mAh g −1 at 5 C, and remarkable cycling stability with 90.44% capacity retention over 700 cycles. Coin cells with high sulfur loading, 4.1 mg cm −2, and pouch cells with 0.1 Ah capacities are further produced to validate their superior cycling stability. In addition, it is demonstrated here that CoFeP@CN hosts greatly alleviate the often overlooked issues of low energy efficiency and serious self‐discharging in LSBs. Abstract : Bimetallic phosphide CoFeP nanocrystals are supported on carbon nitride tubular (t‐CN) nanostructures as a Mott–Schottky catalyst to regulate the lithium polysulfide (LiPS) conversion reaction. The built‐in electric field at the CoFeP/t‐CN interphase significantly promotes catalytic activity, abundant lithiophilic/sulfiphilic sites effectively trap soluble LiPS, and tubular geometry adequately accommodates volume change during the reaction. Consequently, robust lithium–sulfur batteries are obtained.