Ferromagnetic Bimetallic Catalysts Enhance the Overall Performance of Lithium–Sulfur Batteries under a Magnetic Field
Guowen Sun, Guowen Sun, Chaoyue Zhang, Mengjing Jin, Jiayue Li, Xiao Jun Pan, Andreu Cabot, Gengzhi Sun, Gengzhi Sun, Jinyuan Zhou
Abstract
Sluggish reaction kinetics and severe dendrite growth are two main obstacles that hinder lithium–sulfur batteries (LSBs) from practical applications. Here, unconventionally d–p hybridized ferromagnetic Fe 3 M (M = Al, Si, Ga, Ge, Sn) materials are studied as the electrocatalysts and conductive scaffolds for LSBs. This reveals that under a magnetic field, the d–p hybridization can be obviously enhanced via the electron cloud overlap between M and Fe atoms around the Fermi level, thereby leading to highly improved kinetics of the entire Li–S reactions. Furthermore, the magnetic field and magnetized Fe 3 M can locally regulate the diffusion pathways of Li + through the Lorentz force, facilitating uniform lithium deposition. With Fe 3 Ga as the optimal option, under a magnetic field of 280 mT, the Fe 3 Ga@CNF/S cathode delivers specific capacities of 1343.3 and 1091.7 mA h g –1, respectively, at 0.1C and 3.0C, along with an ultralow capacity decay rate of only 0.0065% for 300 cycles at 10.0C, while the Fe 3 Ga@CNF/Li anode maintains a low overpotential of 24.5 mV over 100 days of cycling at 5 mA cm –2 . Consequently, the performances of the Li–S full cell with the Fe 3 Ga@CNF/S cathode and the Fe 3 Ga@CNF/Li anode are significantly improved, producing a capacity of 1027.1 mA h g –1 at 0.2C and 657.5 mA h g –1 at 3.0C, and a Li–S pouch cell with a sulfur loading of 0.146 g delivers a high specific energy density of 317 Wh kg –1 when tested under the magnetic field.