N -Phenyl naphthalene diimide pendant polymer as a charge storage material with high rate capability and cyclability
- PDF / 452,080 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 12 Downloads / 173 Views
Research Letter
N-Phenyl naphthalene diimide pendant polymer as a charge storage material with high rate capability and cyclability Subashani Maniam, School of Chemistry, Monash University, Wellington Rd., Clayton 3800, Victoria, Australia Kouki Oka and Hiroyuki Nishide, Department of Applied Chemistry, Waseda University, Tokyo 169-8555, Japan Address all correspondence to Subashani Maniam, Hiroyuki Nishide at [email protected], [email protected] (Received 2 October 2017; accepted 6 November 2017)
Abstract Pendent-type polymers are attractive materials which allow the flexibility to introduce various redox active moieties that facilitate rapid ion/ electron transport and enable charge storage. Here, we demonstrate naphthalene diimide polymers with polynorbornene backbone having N-phenyl, PNAn 5 and N-(4-nitrophenyl), PNNO 6. Small changes in the molecular design have led to a significant difference in bulk material and device properties. PNNO 6 maintained 80% of its capacity at 1C after 10 cycles in a Li-ion coin cell. PNAn 5 displayed exceptionally high charge capacity and rate capability with excellent cyclability, maintaining almost its theoretical capacity at various C-rates throughout 500 cycles.
Introduction Traditionally, the materials used for electrochemical energy storage systems are metal-based inorganic compounds, such as cobalt, iron, tin, and manganese for lithium battery electrodes and vanadium oxides for redox flow batteries.[1] These inorganic materials rely heavily on the oxidation states of the metals for charge storage and the stabilization of the charge by the counter ion. Although some of these metals work well giving reasonable output voltage, they are relatively scarce, heavy and toxic and their production requires expensive hightemperature processing.[2] Organic materials provide an excellent alternative and versatile platform to be developed into new and exciting materials for charge storage systems. Organic materials can easily be derivatized using simple building blocks to tune the electrochemical properties. Thus the same organic material can be developed for a wide variety of different charge storage devices such as lithium, all organic and multivalent ion batteries.[1] Their performance, however, is limited by the tendency to dissolve in organic electrolytes which compromises charge-discharge cycles or cyclability. It is important for the organic material to be solvated by the electrolyte to allow interpenetration of the counter ions in the electrode. There have been various efforts focused on increasing cyclability by introducing rigid aromatic groups,[3,4] insoluble salts,[5] and macromolecular materials.[6–12] Polymers can be designed to be insoluble in electrolyte solution while still retaining the high theoretical capacity (Ctheor) of small molecules. As a result, polymer-based materials with carbonyl groups have gained popularity, such as anhydrides and quinones which have proven to achieve significant progress.[1,13–15]
Naphthalene diimide (NDI) is the smallest class o
Data Loading...
