Hyperbranched Triphenylamine Polymer for UltraFast Battery Cathode

A novel hyperbranched poly(triphenylamine) (PHTPA) was synthesized, and the electrochemical properties of this material were studied. PHTPA was synthesized by a facile method in a one-step reaction from affordable monomers. Despite all aromatic structures, PHTPA showed good solubility in several organic solvents. The battery performance test of PHTPA showed a high discharge voltage, an ultrafast charge–discharge performance of 100–300 C, and a long cycle life of more than 5000 cycles. Moreover, the addition of the PHTPA to LiFePO4 (LFP) improved the charge-transfer resistance and Warburg coefficient, which is related to the diffusion of lithium ions in LFP, and consequently improved the charge–discharge performance of LFP itself at a high C rate (20–100 C). This behavior is understood to be the result of the organic–inorganic charge transfer. The superior cycle performance of the PHTPA–LFP hybrid cathode was also found. PHTPA will serve as an additive for a high-performance LIB