Compactly Coupled Nitrogen‐Doped Carbon Nanosheets/Molybdenum Phosphide Nanocrystal Hollow Nanospheres as Polysulfide Reservoirs for High‐Performance Lithium–Sulfur Chemistry

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 15; no. 40; pp. e1902491 - n/a
• Main Authors: Sun, Zhonghui, Wu, Xing‐Long, Peng, Zhangquan, Wang, Jiawei, Gan, Shiyu, Zhang, Yuwei, Han, Dongxue, Niu, Li
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.10.2019
• Subjects: Anchoring; Carbon; Decay rate; electrocatalysis; Energy storage; Interfacial energy; lithium sulfide nucleation/dissolution; Lithium sulfur batteries; lithium–sulfur chemistry; Molybdenum; molybdenum phosphide; Nanocrystals; Nanosheets; Nanospheres; Nanotechnology; Nitrogen; nitrogen‐doped carbon nanosheets; Nucleation; Organic chemistry; Phosphides; Polysulfides; Reaction kinetics; Separators; Storage batteries; Storage systems; Sulfur; nitrogen-doped carbon nanosheets; lithium-sulfur chemistry; lithium sulfide nucleation/dissolution; molybdenum phosphide; electrocatalysis
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.201902491

Lithium–sulfur (Li–S) batteries have been disclosed as one of the most promising energy storage systems. However, the low utilization of sulfur, the detrimental shuttling behavior of polysulfides, and the sluggish kinetics in electrochemical processes, severely impede their application. Herein, 3D hierarchical nitrogen‐doped carbon nanosheets/molybdenum phosphide nanocrystal hollow nanospheres (MoP@C/N HCSs) are introduced to Li–S batteries via decorating commercial separators to inhibit polysulfides diffusion. It acts not only as a polysulfides immobilizer to provide strong physical trapping and chemical anchoring toward polysulfides, but also as an electrocatalyst to accelerate the kinetics of the polysulfides redox reaction, and to lower the Li2S nucleation/dissolution interfacial energy barrier and self‐discharge capacity loss in working Li–S batteries, simultaneously. As a result, the Li–S batteries with MoP@C/N HCS‐modified separators show superior rate capability (920 mAh g−1 at 2 C) and stable cycling life with only 0.04% capacity decay per cycle over 500 cycles at 1 C with nearly 100% Coulombic efficiency. Furthermore, the Li–S battery can achieve a high area capacity of 5.1 mAh cm−2 with satisfied capacity retention when the cathode loading reaches 5.5 mg cm−2. This work offers a brand new guidance for rational separator design into the energy chemistry of high‐stable Li–S batteries. 3D hierarchical nitrogen‐doped carbon nanosheets/molybdenum phosphide nanocrystal hollow nanospheres (MoP@C/N HCSs) are introduced to lithium–sulfur (Li–S) chemistry via decorating commercial separators to inhibit polysulfides shuttling. The Li–S batteries based on MoP@C/N HCS‐modified separators exhibit superior electrochemical performance and great potential for practical applications.