Enabling preferential Mg (0002) orientation electrodeposition via constructing a SnS2-engineering host for dendrite-free magnesium metal batteries

Abstract

Magnesium metal has been recognized as a potential candidate for anodes in next-generation high energy density batteries. However, the commercial application of magnesium metal anodes is challenged by uneven magnesium deposition and uncontrolled magnesium dendrite growth. Herein, a three-dimensional (3D) Mg anode host with magnesiophilic SnS₂ nanoarrays grown on carbon cloth (referred to as SnS₂@CC) is designed to address the mentioned obstacles. The concave vertical nanoflower arrays show uniform electric field distribution and magnesium ion flux, combined with the low lattice mismatch between SnS₂ and Mg, effectively promoting magnesium electrodeposition dominated by (0002) basal orientation, thus significantly delaying the dendrite growth. Meanwhile, an alloy layer consisting of Mg₂Sn and MgS species with outstanding Mg affinity and electronic insulation is in situ generated on the surface of the matrix to regulate Mg plating/stripping behavior. Consequently, the SnS₂@CC∥Mg asymmetric cell exhibits excellent rate performance at different current densities, and the Mg@SnS₂@CC symmetric cell presents a stable cycling performance of over 260 h at a high current density of 5 mA cm⁻² with an area capacity of 2.5 mA h cm⁻². For Mo₆S₈∥Mg@SnS₂@CC full batteries, a high coulombic efficiency (CE) of 98% was achieved. This work provides an effective path toward high-performance and dendrite-free Mg metal anode storage systems.