Large π-Conjugated Condensed Perylene-Based Aromatic Polyimide as Organic Cathode for Lithium-Ion Batteries

Abstract

Organic redox-active compounds are promising alternatives to traditional inorganic analogs in organic batteries owing to their high energy density and tunable redox potentials. However, their poor cycling stability due to undesired dissolution in electrolytes and low electronic conductivity limit their applications. Herein, we report the large π-conjugated condensed aromatic structures/extended π-conjugation of perylene-based aromatic polyimide (namely, 5,12-bis­(pyren-1-ylamino)­perylenediimide– hydrazine, BA-PI) as cathode for use in lithium-ion batteries. This cathode is synthesized by one-step polymerization reaction between the aminopyrene-substituted at the 1,7-bay area of perylene-3,4:9,10-tetracarboxylic dianhydride (PTCDA) unit and hydrazine hydrate. The half-cell battery employing BA-PI exhibits an initial discharge capacity of ∼51 mAh g–1 in the potential range of 1.5–3.5 V vs Li+/Li, which is ∼78% of its theoretical value (∼65.46 mAh g–1). Further, a different BA-PI-based cell delivers initial discharge capacity of ∼85 mAh g–1. When the deep-discharging to 0.01 V vs Li+/Li (at the very low voltage of <1.5 V), about 34 Li+ ions can be incorporated into a BA-PI electrode on copper foil as a current collector, exhibiting an extremely high specific capacity of ∼1096 mAh g–1. Moreover, the non-bay-substituted perylene-based aromatic polyimide, as control cathode, has delivered a discharge capacity of ∼129 mAh g–1 and shows good cyclic stability, indicating that such perylene-based aromatic polyimides are promising organic cathode materials for high-capacity lithium–polyimide batteries.

Investigation of ion-electrode interactions of linear polyimides and alkali metal ions for next generation alternative-ion batteries

“…The voltage range was limited to the two-electron reduction of the molecules due to the irreversible decomposition that typically occurs when arylene diimides are further reduced. 28,35–37 As such, two redox couples are observed in each voltammogram, corresponding to reduction to the anion and dianion, respectively.…”

Tuning Electrochemical Properties of Nitroaromatic Cathodes by Function‐Oriented Design for Rechargeable Lithium‐Ion Batteries

“…[55,57] More importantly, a larger π-conjugated structure through the efficient molecular design can significantly improve electric conductivity by the highly delocalized sp 2 -hybridized electrons, which not only populate in the conjugated systems but also among adjacent molecules to render enhanced intramolecular and intermolecular electric correlation. [56,75] Simultaneously, the strong π-conjugated effect is helpful to strengthen the intermolecular interactions (such as π−π or CH•••π interactions), leading to layer-by-layer molecular arrangements. Fast ionic-transport channels are expected to form between the layers, consequently, benefiting the rate capability of organic electrodes.…”

A Polythiophene Material Featuring a Conjugated Carbonyl Side Group as an Anode for Lithium‐Ion Batteries

“…They are expected to be commonly used in electric vehicles, smart grids, and other fields. The cathode and anode materials of commercial lithium‐ion batteries adopt active inorganic materials [1–23] . However, with the increasing demand for high specific energy batteries, developing a new generation of electrode materials is urgent.…”

“…Organic electrode materials currently reported include conductive polymers, [8][9][10] organic sulfides, [11] organic radicals, [12] carbonyl compounds, [13][14][15][16][17][18] nitrogen-containing organics, [19][20][21][22] and others. However, organic small molecule electrode materials have unsatisfactory cycle performance due to their high solubility in organic electrolytes.…”