MoS2/graphene heterostructure with facilitated Mg-diffusion kinetics for high-performance rechargeable magnesium batteries

Mg ions exhibit sluggish kinetics when migrating in most of traditional two-dimensional (2D) layered materials, leading to the dissatisfactory Mg-storage capabilities. Lattice engineering can settle this issue by constructing van der Waals? heterostructures (vdWHs) comprising heterogeneous monolayers, which establish specific ionic diffusion path with lower energy barriers. Herein, MoS2 monolayer and graphene (GR) are alternately overlapped with each other to construct a vdWH with a reduced Mg-diffusion barrier of 0.4 eV, and this brings the diffusion rate 11 orders of magnitude faster than that of pristine MoS2. The facilitated diffusion kinetics delivers a desirable Mg-storage capacity of 210 mAh g-1 at 20 mA g-1, and outstanding rate performance (90 mAh g-1 at 500 mA g-1). Moreover, enhanced structure durability of MoS2/GR allows the chemical reversibility for the repeated intercalation/deintercalation of Mg2+, thus 87% of initial remains after 300 cycles.

Automated summary

Lattice engineering through constructing van der Waals heterostructures can enhance the diffusion rate of Mg ions, improving Mg-storage capabilities. The alternating overlapping of MoS2 monolayer and graphene in a vdWH structure results in significantly reduced Mg diffusion barrier and outstanding rate performance.