Redox-active polyimide-polyether block copolymers as electrode materials for lithium batteries

• Published in: RSC advances Vol. 5; no. 22; pp. 1796 - 1713
• Main Authors: Hernández, Guiomar, Casado, Nerea, Coste, Raphaël, Shanmukaraj, Devaraj, Rubatat, Laurent, Armand, Michel, Mecerreyes, David
• Format: Journal Article
• Language: English
• Published: Royal Society of Chemistry 01.01.2015
• Subjects: atomic force microscopy; Block copolymers; Cathodes; composite polymers; condensation reactions; Current density; Discharge; electric potential difference; Lithium; Lithium batteries; Naphthalene; Physics; polyethylene glycol; Polyimide resins; soot; E-48011 Bilbao; Spain † Electronic supplementary information (ESI) available: Further electrochemical characterization. See; Basque Foundation for Science; Ikerbasque
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c4ra15976d

Redox-active polyimide-polyether multi-block copolymers were synthesized by polycondensation reaction of aromatic dianhydrides with α-ω-diamino poly(ethylene oxide). Polyimide- b -polyether block copolymers showed microphase separation between a hard-polyimide domain and a soft-polyether domain as observed by Atomic Force Microscopy. The block copolymers were investigated as cathodes for polymer/lithium metal batteries. Polymer cathodes were formulated where the block copolymer had a dual role as active material and binder, with a small amount of carbon black (15 wt%). Naphthalene polyimides showed higher discharge voltages, higher specific capacities as well as better cycling performance, compared to pyromellitic polyimides. The longest PEO blocks resulted in a better performance as electrodes. The best performing naphthalene polyimide- b -PEO2000 presented an excellent value of discharge capacity of 170 mA h g −1 , stable after 100 cycles at a current density of 1Li + /5 h and considering the polyimide as the active material. The average discharge plateaus were 2.51 V and 2.37 V vs. Li + /Li. Excellent cyclability of polyimide-polyether block copolymers used as cathode materials in lithium batteries was demonstrated.