A stable 2D nano-columnar sandwich layered phthalocyanine negative electrode for lithium-ion batteries

A porous material composed of nano-columnar Tetra-β-(4-nitro) yttrium phthalocyanine (TNY-Pc) with a sandwich-type layered structure is synthesized and characterized as a negative electrode for rechargeable lithium-ion batteries. The X-ray diffraction and transmission electron microscopy measurement confirmed that the sandwich layer structure has a stable interlayer spacing of 3.07 A. The TNY-Pc negative electrode is stable during charge/discharge, and the lithium cell with the TNY-Pc negative electrode exhibits a high reversible capacity of 730 mAh g−1 with a high initial coulombic efficiency of 96%; the capacity remains 610 mAh g−1 after 1150 cycles. The cell shows a good rate performance with a capacity of 370 mAh g−1 at 3 A g−1. The XRD, TEM and XPS analysis results suggest that N=O double bond on a substituted nitro group of phthalocyanine ring and C=C double bond on phthalocyanine conjugate structure are the two major contributors to the large capacity of lithium intercalation.