Cross‐linking Effects on Performance Metrics of Phenazine‐Based Polymer Cathodes

Abstract

Developing cathodes that can support high charge–discharge rates would improve the power density of lithium‐ion batteries. Herein, the development of high‐power cathodes without sacrificing energy density is reported. N,N′‐diphenylphenazine was identified as a promising charge‐storage center by electrochemical studies due to its reversible, fast electron transfer at high potentials. By incorporating the phenazine redox units in a cross‐linked network, a high‐capacity (223 mA h g−1), high‐voltage (3.45 V vs. Li/Li+) cathode material was achieved. Optimized cross‐linked materials are able to deliver reversible capacities as high as 220 mA h g−1 at 120 C with minimal degradation over 1000 cycles. The work presented herein highlights the fast ionic transport and rate capabilities of amorphous organic materials and demonstrates their potential as materials with high energy and power density for next‐generation electrical energy‐storage technologies.

Dihydrophenazine‐Based Copolymers as Promising Cathode Materials for Dual‐Ion Batteries

“…Among different types of organic batteries, dual‐ion batteries with the cathodes based on polymeric aromatic amines have arisen as one of the most promising solutions due to their high oxidation‐reduction potentials of more than 3 V versus Li + /Li, [ 17–23 ] excellent rate capabilities, [ 18,19 ] good capacity retention, [ 17 ] and relatively high energy densities. [ 20–23 ]…”

“…[ 20,24,25 ] In the recent studies it was shown that hyperbranched polymers deliver higher capacities and provide better cycling stability than linear polymeric chains. [ 23,26 ]…”

“…A recent flow of scientific publications reflects a growing interest in materials incorporating dihydrophenazine moieties [ 20–23 ] due to higher specific capacities of these cathodes reached in lithium [ 23 ] and potassium [ 21 ] batteries compared with other polymeric aromatic amines. Moreover, the use of electrically conductive polyamine‐based materials allows for substantial increasing the content of organic active material in the electrode composite, which is already approaching the benchmarks established for conventional inorganic cathodes.…”

“…Among different types of organic batteries, dual-ion batteries with the cathodes based on polymeric aromatic amines have arisen as one of the most promising solutions due to their high oxidation-reduction potentials of more than 3 V versus Li þ /Li, [17][18][19][20][21][22][23] excellent rate capabilities, [18,19] good capacity retention, [17] and relatively high energy densities. [20][21][22][23] A recent flow of scientific publications reflects a growing interest in materials incorporating dihydrophenazine moieties [20][21][22][23] due to higher specific capacities of these cathodes reached in lithium [23] and potassium [21] batteries compared with other polymeric aromatic amines. Moreover, the use of electrically conductive polyamine-based materials allows for substantial increasing the content of organic active material in the electrode composite, which is already approaching the benchmarks established for conventional inorganic cathodes.…”

“…[20,24,25] In the recent studies it was shown that hyperbranched polymers deliver higher capacities and provide better cycling stability than linear polymeric chains. [23,26] Herein, we present the synthesis and investigation of electrochemical properties of two novel hyperbranched dihydrophenazine copolymers with diphenylamine (PDPAPZ) and phenothiazine (PPTZPZ) moieties in lithium and potassium cells ( are reached under galvanostatic charging and discharging at the high current densities of 5 and 20 A g À1 , respectively. The capacity retention of 86% and 34% after 100 and 25 000 cycles, respectively, features decent operational stability of the batteries.…”