Metal–Organic Framework as a Multifunctional Additive for Selectively Trapping Transition-Metal Components in Lithium-Ion Batteries

To improve the interfacial stability of lithium-ion batteries, a metal–organic framework (MOF) was designed and synthesized as an advanced additive for nickel-rich cathodes to trap the transition metal components. Use of the MOF was found to not compromise the specific capacity of the cells, and cells cycled with a nickel-rich layered oxide embedded with a metal–organic framework exhibited considerably improved cycle retention, even at high temperatures. A systematic analysis demonstrated that only negligible amounts of nickel-ion species migrated from the nickel-rich cathode to the anode surface, and the volume of nickel ions trapped inside the porous structure of the MOF could be determined by quantifying the mass change of the electrode. Finally, the surface degradation triggered by the nickel-ion dissolution was seen to be remarkably suppressed because the MOF improved the surface stability of the nickel-rich cathodes.