Synthesis and charge/discharge properties of cellulose derivatives carrying free radicals

• Published in: Polymer (Guilford) Vol. 49; no. 6; pp. 1490 - 1496
• Main Authors: Qu, Jinqing, Khan, Fareha Zafar, Satoh, Masaharu, Wada, Jun, Hayashi, Hiroyuki, Mizoguchi, Kenji, Masuda, Toshio
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 17.03.2008; Elsevier
• Subjects: Applied sciences; Cellulose and derivatives; Cellulose derivatives; Charge/discharge properties; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Natural polymers; Organic radical battery; Physicochemistry of polymers; Charge/discharge properties; Cellulose derivatives; Organic radical battery; Nitroxyl; Cellulose(ethyl); Secondary cell; Electrode material; Experimental study; Redox polymer; Discharge charge cycle; Pyrrolidine derivatives; Esterification; Lateral group; Chemical modification; Electrochemical properties; Polyradical; Preparation; Piperidine derivatives; Cellulose organic ester; EPR spectrum; Cellulose acetate; Cellulose ether; Voltage capacity curve
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2008.01.065

Ethyl cellulose derivatives [EC-T and EC-P] and cellulose acetate derivatives [CA-T and CA-P] carrying TEMPO or PROXY radicals (TEMPO=2,2,6,6-tetramethyl-1-piperidinyloxy, PROXY=2,2,5,5-tetramethyl-1-pyrrolidinyloxy) were synthesized with moderate number-average molecular weights of 62 400–126 000 in 84–88% yield by the reaction of 4-carboxy-TEMPO or 3-carboxy-PROXY with residual hydroxyl group of ethyl cellulose or cellulose acetate. All the free radical-containing cellulose derivatives demonstrated reversible charge/discharge processes, whose discharge capacities were 42.8–61.1Ah/kg. In particular, the CA-T-based cell displayed two-stage discharge process, and the first-stage discharge capacity reached 29.5Ah/kg which corresponds to 74% of its theoretical value, and that of the total capacity was 61.1Ah/kg which approaches up to 153% of the theoretical value for one-electron redox reaction.