Electromagnetic confinement of polysulfides for shuttle suppression of Li-S batteries

Abstract

The “shuttle effect” is generally harmful for several types of promising next-generation energy storage systems, such as Li-S, Li-I₂, and rechargeable organic batteries. Physical/chemical confinements are useful for anchoring intermediates but not effective for fully utilizing the active materials. Here, we report the electromagnetic confinement of intermediates with iron-doped nickel cobalt oxide nanowire (Fe-doped NiCo₂O₄), a new host material enables high-capacity and long-cycling Li-S battery. In conjunction with theoretical analysis, we use the Fe doping engineering to modulate the interface of the catalyst and explore its effect on the electromagnetic properties and conversion reaction of polysulfides. The high dielectric properties of Fe-doped NiCo₂O₄-CC improve the electron/ion transport and balance the voltage difference at the cathode interface, enhancing the rate performance of the battery. The built-in magnetic field in Fe-doped NiCo₂O₄-CC nanowire creates a favorable substrate-electrolyte interface by modulating the surface reactivity and the diffusion pathway of negative species for strong adsorption of LiPSs, thereby alleviating the shuttle effect and improving cyclic stability. The optimized Fe_0.25Ni_0.75Co₂O₄-CC@S composite cathode exhibits outstanding initial specific capacity (1789.7 mAh g⁻¹ at 0.1 C), excellent rate capability (878.7 mAh g⁻¹ at 5 C), and remarkable cycle performance (724.7 mAh g⁻¹ after 1400 cycles at 2 C, a decay of 0.012 %/cycle). Excellent areal capacity of 13.5 mAh cm⁻² at 0.1 C and low polarization are achieved even at high sulfur loading and lean electrolyte (12.9 mg cm⁻², 3.3 µL/mg). The revealed relationships between doping, electromagnetic properties, adsorption, and catalysis provide new insights to boost the polysulfide conversion reaction and develop high-power Li-S batteries.