Economic synthesis of sub-micron brick-like Al-MOF with designed pore distribution for lithium-ion battery anodes with high initial Coulombic efficiency and cycle stability

Abstract

Metal–organic frameworks (MOFs) have exhibited great potential for lithium-ion batteries (LIBs). However, to date, it is difficult to fabricate MOF electrode materials with regular shape and rational pore distribution by an economic approach, and the currently achieved MOF electrode materials usually have a relatively low initial Coulombic efficiency and poor cycle stability, which is not satisfactory for practical application. In this study, by using the recycled AlCl₃ solution after dealloying treatment of Al–Si alloy, an evenly distributed brick-like Al-MOF with sub-micron size and rational pore distribution was synthesized for the first time. Because of the larger size and more macropores, the as-prepared Al-MOF electrode exhibits superior initial Coulombic efficiency as high as 96.6% for LIB anodes. Moreover, on account of the irregular crystal defects at the edge of the designed macropores, which result from unstable connection between the inorganic nodes (AlO₆ octahedral cluster) and the organic linkers (PTA) and result in the formation of spherical nano-sized particles with better structural stability, the electrode materials show excellent cycle stability with discharge attenuation rate of 0.051%. The electrochemical performance considerably outperforms that of reported Al-MOF anodes and some representative MOF anodes in other studies. The robust realization of high initial Coulombic efficiency and cycle stability defines a critical step to capturing the full potential of MOF electrode materials in practical LIBs.