Advanced Energy MaterialsVolume 6, Issue 9 1502094 Communication New Processable Phenanthridinone-Based Polymers for Organic Solar Cell Applications Maxime Guérette, Maxime Guérette Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorAhmed Najari, Ahmed Najari Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorJulie Maltais, Julie Maltais Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorJean-Rémi Pouliot, Jean-Rémi Pouliot Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorStéphane Dufresne, Stéphane Dufresne Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorMartin Simoneau, Martin Simoneau Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorSimon Besner, Simon Besner Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorPatrick Charest, Patrick Charest Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorMario Leclerc, Corresponding Author Mario Leclerc Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaE-mail: Mario.Leclerc@chm.ulaval.caSearch for more papers by this author Maxime Guérette, Maxime Guérette Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorAhmed Najari, Ahmed Najari Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorJulie Maltais, Julie Maltais Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorJean-Rémi Pouliot, Jean-Rémi Pouliot Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorStéphane Dufresne, Stéphane Dufresne Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaSearch for more papers by this authorMartin Simoneau, Martin Simoneau Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorSimon Besner, Simon Besner Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorPatrick Charest, Patrick Charest Institut de recherche d'Hydro-Québec (IREQ), Varennes, J3X 1S1 CanadaSearch for more papers by this authorMario Leclerc, Corresponding Author Mario Leclerc Département de Chimie, Université Laval, Québec, QC, G1V 0A6 CanadaE-mail: Mario.Leclerc@chm.ulaval.caSearch for more papers by this author First published: 08 February 2016 https://doi.org/10.1002/aenm.201502094Citations: 39Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract New phenanthridinone-based polymers are designed and synthesized by direct (hetero)arylation polymerization for photo­voltaic applications. Bulk-hetero­junction solar cells prepared in air and a random terpolymer (P3) blended with PC71BM in o-dichlorobenzene lead to a power conversion efficiency (PCE) up to 6.7%. When the same polymer is processed with PC61BM in o-xylene with blade-coating in a chlorine-free system, a PCE of 4.7% is observed. Citing Literature Supporting Information As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Filename Description aenm201502094-sup-0001-S1.pdf1.6 MB Supplementary Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume6, Issue9May 11, 20161502094 RelatedInformation

Polymers based on thieno[3,4‐ c ]pyrrole‐4,6‐dione derivatives are interesting and promising candidates for organic bulk heterojunction solar cells. Herein, a series of push–pull conjugated polymers based on thieno[3,4‐ c ]pyrrole‐4,6‐dione (TPD), furo[3,4‐ c ]pyrrole‐4,6‐dione (FPD), and selenopheno[3,4‐ c ]‐pyrrole‐4,6‐dione (SePD) have been synthesized by direct heteroarylation polymerization and fully characterized. The impacts of both the heteroatom (sulfur, oxygen, and selenium) and the side chain (branched or linear) of [3,4‐ c ]pyrrole‐4,6‐dione unit on the electro‐optical properties have been investigated. Among polymers developed, two new highly processable terthiophene–SePD ( P4 ) and dithienosilole–SePD ( P9 ) copolymers led to air‐processed polymer solar cells with power conversion efficiencies of 5.1% and 7.1% using the following inverted configuration: ITO/ZnO/Polymer:PCBM/MoO 3 /Ag. These promising results make P4 and P9 good candidates for further upscaling and device optimization.

LiMn1.5Ni0.5O4 (LMN) has attracted considerable attention as 5-volt cathode materials for Li-ion batteries. Here, the coating of nano LiFePO4 (LFP) onto the surface of the spinel particles is reported for the first time. Two processes were used to prepare LFP-coated LMN: a traditional sol-gel method in Ar and a mechano-fusion dry process, which provides a simple way to obtain surface coating for battery materials. Surface elemental analyses indicate that nano-LFP is intimately covered on the LMN surface. LiMn1.5Ni0.5O4 showed better rate property especially at high rate (>10C) after LiFePO4 coating. Good performance such as 82 mAh g-1 of capacity was still obtained for the LiFePO4-coated LiMn1.5Ni0.5O4 with 75% of capacity retention after 140 cycles under 1C.

C-LiFePO4 nanoparticles were used as surface coating for the LiMn1.5Ni0.5O4 spinel. However, it is impossible to prepare LiFePO4-coated LiMn1.5Ni0.5O4 by traditional sol-gel methods in Ar. Therefore, we used a new mechano-fusion dry process that provides a simple way to obtain surface coating for battery materials. Surface elemental analyses indicate that LiFePO4 nanoparticles were not simply mixed with the LiMn1.5Ni0.5O4, but successfully coated on its surface. This new composite was tested as a cathode for Li-ion batteries. LiMn1.5Ni0.5O4 showed better capacity retention after LiFePO4 coating, especially at high rate (>10C). After 100 cycles at 1C, the capacity declined from 105 to 65 mAh g(-1) for the bare LiMn1.5Ni0.5O4. In contrast, 82 mAh g(-1) of capacity was still obtained for the LiFePO4-coated LiMn1.5Ni0.5O4 with 75% of capacity retention after 140 cycles under 1C. The results suggest that the improved performance is due to the improvement of the surface conductivity due to the carbon coated LiFePO4 covering, end the protection against reactions of LiMn1.5Ni0.5O4 with the electrolyte. (C) 2011 Elsevier B.V. All rights reserved.

LiFePO4 (LFP) nano-particles have been obtained by grinding ingot synthesized in the molten state. This process, followed by jet milling, and then wet milling, provides a simple way to obtain powders with monitored size of the particles in the whole range from macroscopic to 25 nm, although at this stage, we find that these particles tend to segregate to form secondary particles of size ~100 nm. The electrochemical performance of LFP particles has been evaluated in Li/1M LiPF6 in EC:DEC (1:1)/C-LiFePO4 cells. After carbon coating, LFP particles can be obtained free from any impurity, with a high rate capability. Even with an amount of carbon limited to 2 wt.% appropriate to commercial batteries, the capacity is 157 mAh/g at 0.1C; 58 mAh/g at 10C without capacity fading after 60 cycles.

Negative electrodes containing SiOx were investigated as alternative negative electrodes to carbon for Li-ion batteries. The results obtained on the effect of binders and carbon additives on the electrochemical performance (i.e., reversible capacity, coulombic efficiency, charge–discharge rate capability) of the SiOx–graphite electrode and SiOx electrode are presented. SEM analysis that utilizes facilities for in situ and ex situ studies were applied to better understand the performance and cycle life of the SiOx-based electrodes. The SEM analysis clearly showed that the SiOx particles expand and contract during charge–discharge cycling, and that some of the particles undergo mechanical degradation during this process. The SiOx–graphite electrode with polyimide binder exhibited a stable capacity of 600mAhg−1 during high-rate charge–discharge from C/4 to 1C. These results suggest that the use of a flexible binder like polyimide and reasonably small SiOx particles (nano-particles) facilitates improved cycle life and higher rate capability.

LiFePO4 nano-particles have been prepared by grinding ingot synthesized in the molten state. Formatting 25-nanometer particles was obtained by subsequent jet and wet milling. These primary particles tend to segregate to form secondary particles of size ∼100 nm, for which surface effects become increasingly important. Study of the electrochemical properties of Li//LiFePO4 cells showed that the cell performance appeared to be strongly dependant of the synthetic route used. The best electrode material formed by wet milling followed by 2 wt.% carbon coating delivered discharge capacity of 157 mAh g-1 at C/10 rate without capacity fading after 60 cycles.

We report a Li-ion battery that can be charged within few minutes, passes the safety tests, and has a very long shelf life. The active materials are nanoparticles of LiFePO4 (LFP) and Li4Ti5O12 (LTO) for the positive and negative electrodes, respectively. The LiFePO4 particles are covered with 2wt.% carbon to optimize the electrical conductivity, but not the Li4Ti5O12 particles. The electrolyte is the usual carbonate solvent. The binder is a water-soluble elastomer. The “18650” battery prepared under such conditions delivers a capacity of 800mAh. It retains full capacity after 20,000 cycles performed at charge rate 10C (6min), discharge rate 5C (12min), and retains 95% capacity after 30,000 cycles at charge rate 15C (4mn) and discharge rate 5C both at 100% DOD and 100% SOC.

LiFePO4 (LFP) particles were obtained by grinding ingot synthesized in the molten state. This process, followed by jet milling, and then wet milling, provides a simple way to obtain powders with controlled particle size in the range from macroscopic to 25nm. However, at this time, we find that these particles tend to agglomerate to form secondary particles of size ∼100nm. The particles obtained by this process are characterized by X-ray diffraction (XRD). In situ and ex situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of milling was also investigated by analysis of physical properties using infrared spectroscopy (FTIR) and magnetic measurements. The electrochemical performance was evaluated in cells containing Li/1M LiPF6 in EC:DEC (1:1)/C-LiFePO4. After carbon coating, the LFP particles which are free of impurities, exhibit high-rate capability. Even with a limited amount of carbon (2wt.%) appropriate for commercial batteries, the capacity is 157mAhg−1 at 0.1C, 120mAhg−1 at 10C, without capacity fading after 60 cycles.

Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is ≥40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO4 cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155mAhg−1 at C/12 is obtained with cells having at least some organic electrolyte compared to only 124mAhg−1 with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO4//Li4Ti5O12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2C rate. This study indicates that safety and electrochemical performance of the Li-ion battery can be improved by using mixed IL and organic solvents.

The combination of graphite or silicon monoxide (SiO)/graphite=1/1 mixture with a solvent-free solid polymer electrolyte (SPE) was fabricated using a new preparation process, involving precoating the electrode with vapor-grown carbon fiber (VGCF) and binders (polyvinyl difluoride: PVdF or polyimide: PI), followed by the overcoating of the SPE. The reversible capacity of [graphite | SPE | Li] and [SiO/graphite | SPE | Li] cells were >360 and >1000mAhg−1 with 78% and 77% for the 1st Coulombic efficiency, respectively. The reversible capacities were 75% at the 250th cycle for [graphite | SPE | Li] and 72% at the 100th cycle for [SiO/graphite | SPE | Li]. The electrode used was compatible with that of the conventional liquid electrolyte system, and the SPE film could be formed on the electrode by the continuous overcoating process, which will lead to a low-cost electrodes and low-cost battery production. The solid-state lithium-ion polymer battery (SSLiPB) developed in this study, which consisted of [LiFePO4 | SPE | graphite], showed the reversible capacity of 128mAhg−1 (based on the LiFePO4 capacity) with favorable cycle performance.

The effect of H2O on carbon-coated LiFePO4 particles was investigated by chemical analysis, structural analysis (X-ray diffraction, SEM, TEM), optical spectroscopy (FTIR, Raman) and magnetic measurements. Upon immersion in water, part of the product floats while the main part sinks. Both the floating and the sinking part have been analyzed. We find that the floating and sinking part only differ by the amount of carbon that partly detaches from the particles upon immersion in water. Exposure to H2O results in rapid attack, within minutes, of the surface layer of the particles, because the particles are no longer protected by carbon. The deterioration of the carbon coat is dependent on the synthesis process, either hydrothermal or solid-state reaction. In both cases, however, the carbon coat is permeable to water and fails to protect the surface of the LiFePO4 particles. The consequence is that this immersion results in the chemical attack of LiFePO4, but is restricted to the surface layer of the particles (few nanometers-thick). In case the particles are simply exposed to humid air, the carbon coat protects the particles more efficiently. In this case, the exposure to H2O mainly results in the delithiation of the surface layer, due to the hydrophilic nature of Li, and only the surface layer is affected, at least for a reasonable time of exposure to humid air (weeks). In addition, within this timescale, the surface layer can be chemically lithiated again, and the samples can be dried to remove the moisture, restoring the reversible electrochemical properties.

The electrochemical properties of LiFePO4 cathodes with different carbon contents were studied to determine the role of carbon as conductive additive. LiFePO4 cathodes containing from 0 to 12% of conductive additive (carbon black or mixture of carbon black and graphite) were cycled at different C rates. The capacity of the LiFePO4 cathode increased as conductive additive content increased. Carbon increased the utilization of active material and the electrical conductivity of electrode, but decreased volumetric capacity of electrode. This composition (LiFePO4 with 3 wt % of carbon and 3 wt % of Graphite) is suitable for HEV application. (C) 2005 The Electrochemical Society.

The aging and performance of natural graphite/PEO-based gel electrolyte/LiFePO4 cells have been reported. The gel polymer electrolytes have been produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4-EC/GBL exhibits high reversible capacity (345mAh/g) and high coulombic efficiency (91%). The LiFePO4 cathode.in the same gel-polymer exhibits a reversible capacity of 150 mAh/g and 83% coulombic efficiency. Better performance has been obtained at high-rate discharge with 6% carbon additive in the cathode. However, the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature. Li/polymer/LiFePO4 has an excellent stable cycle life.

The performance of natural graphite-fibers/PEO-based gel electrolyte/LiFePO4 cells (7mAh, 4cm2) is reported. The gel polymer electrolytes were produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite-fiber composite anode in gel electrolyte containing 1.5M LiFSI-EC/GBL (1:3) exhibited high reversible capacity (361mAhg−1) and high Coulombic efficiency (92%). The LiFePO4 cathode in the same gel polymer exhibited a reversible capacity of 161mAhg−1 and 93% Coulombic efficiency. A 1.5M solution of LiFSI in ethylene carbonate (EC)/γ-butyrolactone (GBL) (1:3, v/v) mixed solvent is advantageous for use as the electrolyte in the laminated film bag because of its high flame point (135°C), high boiling point (219°C), low vapor pressure and high conductivity (10.2mScm−1 at 20°C). The Li-ion gel polymer battery shows a very low capacity fade of 5% after 500cycles and also has high-rate capability. The Li-ion gel polymer cell using LiFePO4 cathodes is suitable for HEV applications.

The performance of natural graphite/PEO-based gel electrolyte/LiFePO4 cells (5 mAh, 4 cm2) is reported. The gel polymer electrolytes were produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing lithium bis(fluorosulfonyl)imide (LiFSI)-EC + PC + DMC exhibited high reversible capacity (360 mAh/g) and high coulombic efficiency (91.6%). The LiFePO4 cathode in the same gel polymer exhibited a reversible capacity of 160 mAh/g and 92% coulombic efficiency. Better performance was obtained at high-rate discharge with 6% carbon additive (carbon and graphite) in the cathode. The Li-ion gel polymer battery shows a very low capacity fade of 1% after 100 cycles.

Li4Ti5O12 was prepared by a solid-state reaction of ternary precursor materials TiO2, Li2CO3 and carbon. The precursors were mixed by two methods—a dry and wet process. Different types of carbons (carbon black, high-surface-area carbon, graphite and carbonized polymer) were used. The particle shape and size of the product were connected to the carbon type used in the synthesis. The electrochemical performance and the role of particle shape and size were investigated. The weight loses of ternary powder was monitored by TGA to establish the optimum synthesis temperature. XRD diffraction was used to study the TiO2 residue in the final powder.