Abstract Polysulfides shuttle and Li2S passivation are considered key problems of lithium–sulfur (Li–S) batteries, seriously hindering sulfur recycle for practical applications. However, the prevailing strategies introducing electrocatalysts focus mainly on polysulfides shuttle effect, whereas Li2S passivation involving solid conversions with high energy barriers has been seldomly studied and remains challenging. Herein, we propose that applying magnetic field (MF) to weak ferromagnetism α-Fe2O3 shows enhanced effect not only suppressing polysulfides shuttle but also alleviating Li2S passivation by synchronously catalyzing polysulfides conversion and Li2S deposition/dissociation. Experimental and theoretical studies reveal that MF can promote the consistent alignment of magnetic domain orientations in α-Fe2O3 and enhance the electron spin polarization of the Fe 3d, which shifts the center of the Fe d-band towards the Fermi level and increases the hybridization degree between Fe 3d and S 3p in α-Fe2O3-Li2S6 or α-Fe2O3-Li2S, thus enhancing the adsorption and catalysis of polysulfides and solid products. As a result, after using a 400 mT MF, the α-Fe2O3/S cathode shows outstanding cycling stability and excellent rate capability. The research demonstrates that MF-guided electrocatalysis represents an effective solution to the challenging problems of Li–S batteries.
Liao et al. (2026) studied this question.