Facile synthesis of ternary transition metal-organic framework and its stable lithium storage properties

Abstract

Metal-organic frameworks (MOFs) are considered as promising electrode materials due to their high controllability and regular pore structure. Nevertheless, limited by the low ionic conductivity of organic frameworks and the huge volume change caused by the conversion reaction of metal ions with Li+, their long-term stability and rate performance are not satisfactory. In this paper, a regular micron rod-shaped nickel, iron and manganese benzene-1,2,4,5-tetracarboxylate trimetallic organic framework (NiFeMn-pma) was synthesized by a one-pot method. It belongs to monoclinic symmetry and P21/n space group, in which metal ions are coordinated with different oxygen atoms on the carboxyl group of pyromellitic acid to form a three-dimensional structure. Remarkably, thanks to the change of the lithium storage form from a conversion reaction to an intercalation reaction based on a carboxyl group and a benzene ring, NiFeMn-pma exhibits a high capacity of 802.1 mAh g-1 and excellent cycle stability (624 mAh g-1 at 100 ​mA ​g-1 over 100 cycles) as an anode material for lithium ion batteries (LIBs). Compared with single metal MOF (Ni-pma) and bimetal MOF (NiFe-pma), tri-metal MOF (NiFeMn-pma) exhibits enhanced rate performance, which is attributed to the synergistic effect of multi-metal mixing sites. Meanwhile, the surface of NiFeMn-pma electrode is porous after 100 cycles, which can significantly improve the penetration of electrolyte and promote the migration of lithium ions. The research paved the way for the potential application of MOF materials in lithium-ion batteries.