Rational Functionalization of Perylene Diimide for Stable Capacity and Long-term Cycling Performance for Li-ion Batteries

Perylene based dilithium salt of N,N'-bis (glycinyl) perylene diimide (Li2-PDI) was synthesized and studied as an electrode material for lithium-ion batteries. The CH2COOLi functionalization of perylene diimide is a simple strategy to mitigate the dissolution of the monomer in the electrolyte. The Li2-PDI electrode exhibits excellent capacity retention behaviour and delivers a stable specific capacity of 101 mAh g−1 after 100 cycles at a current density of 17 mA g−1, which is 98% of theoretical specific capacity. A remarkably stable capacity of 87 mAh g−1 was observed even after 1000 cycles with 100% coulombic efficiency at a current density of 200 mA g−1. The reversible electrochemical lithiation/delithiation mechanism of Li2-PDI was studied by ex-situ XRD and FT-IR spectroscopic techniques.

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