In-situ dynamic catalysis electrode electrolyte interphase enabling Mg2+ insertion in 2D metal–organic polymer for high-capacity and long-lifespan magnesium batteries

Abstract

Rechargeable magnesium battery is regarded as the promising candidate for the next generation of high-specific-energy storage systems. Nevertheless, issues related to severe Mg-Cl dissociation at the electrolyte–electrode interface impede the insertion of Mg2+ into most materials, leading to severe polarization and low utilization of Mg-storage electrodes. In this study, a metal–organic polymer (MOP) Ni-TABQ (Ni-coordinated tetramino-benzoquinone) with superior surface catalytic activity is proposed to achieve the high-capacity Mg-MOP battery. The layered Ni-TABQ cathode, featuring a unique 2D π-d linear conjugated structure, effectively reduces the dissociation energy of MgxCly clusters at the Janus interface, thereby facilitating Mg2+ insertion. Due to the high utilization of active sites, Ni-TABQ achieves high capacities of 410 mAh/g at 200 mA g−1, attributable to a four-electron redox process involving two redox centers, benzoid carbonyls, and imines. This research highlights the importance of surface electrochemical processes in rechargeable magnesium batteries and paves the way for future development in multivalent metal-ion batteries.