Poly(arylamine-imide)s Cathode Materials for Lithium-Ion Batteries with High Average Voltage and Long Cycle Life

Abstract

Two poly(arylamine-imide)s, poly(N,N,N′,N′-tetraphenyl-1,4-benzenediamine naphthalenediimide) (PDDP-NI) and poly(N,N,N′,N′-tetraphenyl-1,4-benzenediamine perylenediimide) (PDDP-PI), were successfully prepared by condensation polymerization of an amine monomer N,N,N′,N′-tetraphenyl-1,4-benzenediamine (DDP) with dianhydride monomer 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) or 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA). The DDP units in the polymer can reversibly dope/dedope the PF6 − anion, while the naphthalenediimide (NI) unit or perylene diimide (PI) unit can reversibly insert/extract the lithium cation. The lithium ion half-cells based on the polymer cathode and the lithium anode are assembled and the electrochemical properties are tested. Due to the high voltage of the DDP unit in the polymer backbone, lithium-ion half-cells based on PDDP-NI and PDDP-PI cathodes provide a high average discharge voltage of about 3.2 V. Moreover, the as-prepared polymer materials exhibit long-cycle performance, PDDP-NI remains 89% capacity after 500 cycles at 10 C and PDDP-PI maintains 98% capacity after 1000 cycles at 10 C, furthermore, their coulombic efficiency close to 100% at all current rates tested, which shows that these organic cathode materials have potential applications in long-cycle lithium-ion batteries.