Arylacetylene‐Substituted Naphthalene Diimides with Dual Functions: Optical Waveguides and n‐Type Semiconductors

New arylacetylene‐substituted naphthalene diimides (NDIs) 1–6 , with both light‐emitting and semiconducting functions, are reported. Among them, the crystal structure of 1 was determined. On the basis of their reduction potentials and thin‐film absorption spectra, the HOMO/LUMO energies of these modified NDIs were estimated. The results reveal that their HOMO/LUMO energies are slightly affected by the flanking aryl groups. The emission colors of these NDIs vary from green to red, and interestingly, they show aggregation‐induced emission enhancement behavior with fluorescence quantum yields reaching 9.86 % in the solid state. Microrods of 1 , 3 , and 5 show typical optical wave‐guiding behavior with relatively low optical‐loss coefficients. Organic field‐effect transistors with thin films of these NDIs were fabricated with conventional techniques. The results indicate that thin films of 2 , 4 , and 6 , with long and branched alkyl chains, show air‐stable n‐type semiconducting properties with electron mobilities of up to 0.035 cm² V^?1 s^?1 after thermal annealing, whereas 1 , 3 , and 5 , with short alkyl chains, behave as n‐type semiconductors under a nitrogen atmosphere with electron mobilities of up to 0.075 cm² V^?1 s^?1 after thermal annealing.     

Conjoint use of Naphthalene Diimide and Fullerene Derivatives to Generate Organic Semiconductors for n–type Organic Thin Film Transistors

In this paper, we described the design, synthesis, and characterization of two novel naphthalene diimide (NDI) core-based targets modified with terminal fullerene (C₆₀) yield – so called S4 and S5 , in which NDI bearing 1 and 2 molecules of C₆₀, respectively. The absorption, electrochemical and thin-film transistor characteristics of the newly developed targets were investigated in detail. Both S4 and S5 displayed broad absorption in the 450–500 nm region, owing to the effect of conjugation due to fullerene functionalities. The electrochemical measurement suggested that the HOMO and the LUMO energy levels can be altered with the number of C₆₀ units. Both S4 and S5 were employed as organic semiconductor materials in n-channel transistors. The thin film transistor based on S4 exhibited superior electron mobility (μe) values ranging from 1.20×10⁻⁴ to 3.58×10⁻⁴ cm² V⁻¹ s⁻¹ with a current on-off ratio varying from 10² to 10³ in comparison with the performance of S5 based transistor, which exhibited μe ranging from 8.33×10⁻⁵ to 2.03×10⁻⁴ cm² V⁻¹ s⁻¹ depending on channel lengths.     

n‐Type Conjugated Polymer Based on Dicyanodistyrylbenzene and Naphthalene Diimide Units for All‐Polymer Solar Cells

All polymer solar cells (all‐PSCs), possessing superior mechanical strength and flexibility, offer the commercialization opportunity of the PSCs for flexible and portable devices. In this work, we designed and synthesized two copolymer acceptors based on dicyanodistyrylbenzene (DCB) and naphthalene diimide (NDI) units. The corresponding copolymer acceptors are denoted as PDCB‐NDI812 and PDCB‐NDI1014. The medium band gap copolymer PBDB‐T was selected as donor material for investigation of the photovoltaic performance. Two all‐PSCs devices showed power conversion efficiencies (PCE) of 4.26% and 3.43% for PDCB‐NDI812 and PDCB‐NDI1014, respectively. The improved PCE was ascribed to the higher short‐circuit current (J_SC), greater charge carrier mobility and higher exciton dissociation probability of the PBDB‐T:PDCB‐NDI812 blend film. These results suggest that DCB unit and NDI unit based copolymer acceptors are promising candidates for high performance all‐PSCs.     

Broadband Visible‐Light‐Harvesting trans‐Bis(alkylphosphine) Platinum(II)‐Alkynyl Complexes with Singlet Energy Transfer between BODIPY and Naphthalene Diimide Ligands

A heteroleptic bis(tributylphosphine) platinum(II)‐alkynyl complex ( Pt‐1 ) showing broadband visible‐light absorption was prepared. Two different visible‐light‐absorbing ligands, that is, ethynylated boron‐dipyrromethene (BODIPY) and a functionalized naphthalene diimide (NDI) were used in the molecule. Two reference complexes, Pt‐2 and Pt‐3 , which contain only the NDI or BODIPY ligand, respectively, were also prepared. The coordinated BODIPY ligand shows absorption at 503 nm and fluorescence at 516 nm, whereas the coordinated NDI ligand absorbs at 594 nm; the spectral overlap between the two ligands ensures intramolecular resonance energy transfer in Pt‐1 , with BODIPY as the singlet energy donor and NDI as the energy acceptor. The complex shows strong absorption in the region 450 nm–640 nm, with molar absorption coefficient up to 88 000 M ^?1 cm^?1. Long‐lived triplet excited states lifetimes were observed for Pt‐1 – Pt‐3 (36.9 μs, 28.3 μs, and 818.6 μs, respectively). Singlet and triplet energy transfer processes were studied by the fluorescence/phosphorescence excitation spectra, steady‐state and time‐resolved UV/Vis absorption and luminescence spectra, as well as nanosecond time‐resolved transient difference absorption spectra. A triplet‐state equilibrium was observed for Pt‐1 . The complexes were used as triplet photosensitizers for triplet–triplet annihilation upconversion, with upconversion quantum yields up to 18.4 % being observed for Pt‐1 .     

Cation‐Dependent Stabilization of Electrogenerated Naphthalene Diimide Dianions in Porous Polymer Thin Films and Their Application to Electrical Energy Storage

Porous polymer networks (PPNs) are attractive materials for capacitive energy storage because they offer high surface areas for increased double‐layer capacitance, open structures for rapid ion transport, and redox‐active moieties that enable faradaic (pseudocapacitive) energy storage. Here we demonstrate a new attractive feature of PPNs—the ability of their reduced forms (radical anions and dianions) to interact with small radii cations through synergistic interactions arising from densely packed redox‐active groups, only when prepared as thin films. When naphthalene diimides (NDIs) are incorporated into PPN films, the carbonyl groups of adjacent, electrochemically generated, NDI radical anions and dianions bind strongly to K⁺, Li⁺, and Mg²⁺, shifting the formal potentials of NDI’s second reduction by 120 and 460 mV for K⁺ and Li⁺‐based electrolytes, respectively. In the case of Mg²⁺, NDI’s two redox waves coalesce into a single two‐electron process with shifts of 240 and 710 mV, for the first and second reductions, respectively, increasing the energy density by over 20 % without changing the polymer backbone. In contrast, the formal reduction potentials of NDI derivatives in solution are identical for each electrolyte, and this effect has not been reported for NDI previously. This study illustrates the profound influence of the solid‐state structure of a polymer on its electrochemical response, which does not simply reflect the solution‐phase redox behavior of its monomers.     

Electroenzymatic Nitrogen Fixation Using a MoFe Protein System Immobilized in an Organic Redox Polymer

We report an organic redox‐polymer‐based electroenzymatic nitrogen fixation system using a metal‐free redox polymer, namely neutral‐red‐modified poly(glycidyl methacrylate‐co‐methylmethacrylate‐co‐poly(ethyleneglycol)methacrylate) with a low redox potential of ?0.58 V vs. SCE. The stable and efficient electric wiring of nitrogenase within the redox polymer matrix enables mediated bioelectrocatalysis of N₃^?, NO₂^? and N₂ to NH₃ catalyzed by the MoFe protein via the polymer‐bound redox moieties distributed in the polymer matrix in the absence of the Fe protein. Bulk bioelectrosynthetic experiments produced 209±30 nmol NH₃ nmol MoFe^?1 h^?1 from N₂ reduction. ¹⁵N₂ labeling experiments and NMR analysis were performed to confirm biosynthetic N₂ reduction to NH₃.     

Cyclic Naphthalene Diimide with a Ferrocene Moiety as a Redox-Active Tetraplex-DNA Ligand

Cyclic naphthalene diimides (cNDIs), with a ferrocene moiety (cFNDs) and different linker lengths between the ferrocene and cNDI moieties, were designed and synthesized as redox-active, tetraplex-DNA ligands. Intramolecular stacking was observed between ferrocene and the NDI planes, which could affect the binding properties for G-quadruplexes. Interestingly, the circular dichroism spectrum of one of these compounds clearly shows new Cotton effects around 320–380 and 240 nm, which can be considered a direct evidence of intramolecular stacking of ferrocene and the NDI. Regarding recognition of hybrid G-quadruplexes, the less rigid structures (longer linkers) show higher binding affinity (10⁶ m ⁻¹ order of magnitude). All new compounds show higher selectivity for G4 during electrochemical detection than noncyclic FND derivatives, which further identifies the redox-active potentiality of the cFNDs. Two of the three compounds tested even show preferential inhibition of cell growth in cancer cells over normal cells in a low concentration range, highlighting the potential for bioapplications of these cFNDs.     

Side chain engineering of naphthalene diimide–bithiophene‐based polymer acceptors in all‐polymer solar cells

Two novel polymeric acceptors based on naphthalene diimide (NDI) and 2.2′‐bithiophene, named as P(NDI2THD‐T2) and P(NDI2TOD‐T2), were designed and synthesized for all polymer solar cells application. The structural and electronic properties of the two acceptors were modulated through side‐chain engineering of the NDI units. The optoelectronic properties of the polymers and the morphologies of the blend films composed of the polymer acceptors and a donor polymer PTB7‐Th were systemically investigated. With thiophene groups introduced into the side chains of the NDI units, both polymers showed wider absorption from 350 nm to 900 nm, compared with the reference polymer acceptor of N2200. No redshift of absorption spectra from solutions to films indicated reduced aggregation of the polymers due to the steric hindrance effect of thiophene rings in the side chains. The photovoltaic performance were characterized for devices in a configuration of ITO/PEDOT:PSS/PTB7‐Th:acceptors/2,9‐bis(3‐(dimethylamino)propyl)anthra[2,1,9‐def:6,5,10‐def]diisoquinoline‐1,3,8,10(2H,9H)‐tetraone (PDIN)/Al. With the addition of diphenyl ether as an additive, the power conversion efficiencies (PCEs) of 2.73% and 4.75% for P(NDI2THD‐T2) and P(NDI2TOD‐T2) based devices were achieved, respectively. The latter showed improved J_sc, Fill Factor (FF), and PCE compared with N2200 based devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3679–3689     

The First Conjugated Allene Polymer

A novel conjugated polymer with allene moieties in the polymer main chain, poly(4,4′‐biphenylylene‐1,3‐diphenylpropadien‐1,3‐ylene), was synthesized from 1,3‐bis(4‐bromophenyl)‐1,3‐diphenylpropadiene by dehalogenative polycondensation using Ni(cod)₂. The polymer shows good solubility in common organic solvents, good processability for making thin films, intense blue fluorescence in solution and acid sensitivity resulting in coloration. The conductivity increased by an order of 10⁴ upon exposure to trifluoroacetic acid vapor.     

A new polymer acceptor containing naphthalene diimide and 1,3,4‐thiadiazole for all‐polymer solar cells

A n‐type conjugated polymer containing naphthalene diimide (NDI) and 1,3,4‐thiadiazole (TZ) moieties, named PNTZ, has been synthesized and applied for all‐polymer solar cells (all‐PSCs). By the incorporation of TZ unit into the polymer main chains, the lowest unoccupied molecular orbital level of this polymer has been adjusted effectively. In addition, the electron‐acceptor PNTZ shows a broad absorption spectrum in the range of 300–700 nm, and possesses complementary absorption spectrum with the electron‐donor PTB7‐Th. On the basis of PNTZ as the acceptor and PTB7‐Th as the donor, the all‐PSCs are fabricated. After optimization, the well blend morphologies with a continuous D/A interpenetrating network are observed and the best all‐PSC device exhibits a power conversion efficiency of 4.35% with a high short‐circuit current density of 13.26 mA cm^?2. This research demonstrates that the TZ‐containing polymer PNTZ is a promising non‐fullerene acceptor for high efficiency all‐PSCs. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 990–996     

Structural characterization and photochromic behaviour of a novel compound based on a π‐acidic naphthalene diimide derivative and a double hydroxide‐bridged dinuclear AlIII aqua ion cluster

Noncovalent interactions, such as π–π stacking interactions, C—H…π interactions and hydrogen bonding, are important driving forces for self‐assembly in the construction of functional supermolecules and materials, especially in multicomponent supramolecular systems. Herein, a novel compound based on a π‐acidic naphthalene diimide derivative and a double hydroxide‐bridged dinuclear Al³⁺ aqua ion cluster, namely bis[N,N′‐bis(2‐sulfonatoethyl)‐1,4,5,8‐naphthalene diimide] di‐μ‐hydroxido‐bis[tetraaquaaluminium(III)] tetrahydrate, (C₁₈H₁₂N₂O₁₀S₂)₂[Al₂(OH)₂(H₂O)₈]·4H₂O, was obtained using the above‐mentioned common noncovalent interactions, as well as uncommon lone‐pair–π interactions. Functional molecular modules were connected by these noncovalent interactions to generate obvious photochromic properties. The compound was prepared by the self‐assembly of N,N′‐bis(2‐sulfoethyl)‐1,4,5,8‐naphthalene diimide and Al(NO₃)₃·9H₂O under mixed solvothermal conditions, and was characterized in detail by single‐crystal X‐ray diffraction, powder X‐ray diffraction and FT–IR spectroscopy. The thermal stability and photochromic properties were also investigated; furthermore, in‐situ solid‐state UV–Vis absorption spectroscopy and electron spin resonance (ESR) were used to clarify the photochromic mechanism.     

Electrochemical storage properties of polyaniline-, poly(N-methylaniline)-, and poly(N-ethylaniline)-coated pencil graphite electrodes

Three types of conducting polymers, polyaniline (PANI), poly(N-methylaniline) (PNMA), poly(N-ethylaniline) (PNEA) were electrochemically deposited on pencil graphite electrode (PGE) surfaces characterized as electrode active materials for supercapacitor applications. The obtained films were electrochemically characterized using different electrochemical methods. Redox parameters, electro-active characteristics, and electrostability of the polymer films were investigated via cyclic voltammetry (CV). Doping types of the polymer films were determined by the Mott-Schottky method. Electrochemical capacitance properties of the polymer film coating PGE (PGE/PANI, PGE/PNMA, and PGE/PNEA) were investigated by the CV and potentiostatic electrochemical impedance spectroscopy (EIS) methods in a 0.1 M H₂SO₄ aqueous solution. Thus, capacitance values of the electrodes were calculated. Results show that PGE/PANI, PGE/PNMA, and PGE/PNEA exhibit maximum specific capacitances of 131.78 F g^?1 (≈ 436.50 mF cm^?2), 38.00 F g^?1 (≈ 130.70 mF cm^?2), and 16.50 F g^?1 (≈ 57.83 mF cm^?2), respectively. Moreover, charge-discharge capacities of the electrodes are reported and the specific power (SP) and specific energy (SE) values of the electrodes as supercapacitor materials were calculated using repeating chronopotentiometry.     

Synthesis and characterization of a photochromic magnesium(II) coordination polymer based on a naphthalene diimide ligand

Naphthalene diimides, which are planar, chemically robust and redox‐active, are an attractive class of electron‐deficient dyes, which can undergo a single reversible one‐electron reduction to form stable radical anions in the presence of electron donors upon irradiation. This makes them excellent candidates for organic linkers in the construction of photochromic coordination polymers. Such a photochromic one‐dimensional linear coordination polymer has been prepared using N ,N ′‐bis(3‐carboxyphenyl)naphthalene‐1,8:4,5‐tetracarboximide (H₂BBNDI). Crystallization of H₂BBNDI with magnesium nitrate in an N ,N ′‐dimethylformamide (DMF)/ethanol/H₂O mixed‐solvent system under solvothermal conditions afforded the one‐dimensional coordination polymer catena‐poly[[bis(dimethylformamide‐κO )magnesium(II)]‐bis[μ‐N‐(3‐carboxylatophenyl)‐N ′‐(3‐carboxylphenyl)naphthalene‐1,8:4,5‐tetracarboximide‐κ²O :O ′]], [Mg(C₂₈H₁₃N₂O₈)₂(C₃H₇NO)₂]_n . The asymmetric unit contains half of a magnesium cation, one HBBNDI⁻ ligand and one DMF molecule. Two partially deprotonated HBBNDI⁻ ligands bridge two magnesium cations to form a one‐dimensional chain. Strong inter‐chain π–π interactions between the naphthalene rings of the HBBNDI⁻ ligand and the imide rings of adjacent chains provide a two‐dimensional structure. The supramolecular three‐dimensional framework is stabilized by π–π interactions between naphthalene rings of neighbouring two‐dimensional supramolecular networks. The complex exhibits a reversible photochromic behaviour, which may originate from the photoinduced electron‐transfer generation of radicals in the HBBNDI⁻ ligand.     

Two‐component molecular crystals from N‐heteroaromatics and nitro­benzoic acids

Five two‐component molecular crystals, benzimidazolium 3‐nitro­benzoate, C₇H₇N₂⁺·C₇H₄NO₄^?, (I), benzimidazolium 4‐nitro­benzoate, C₇H₇N₂⁺·C₇H₄NO₄^?, (II), 1H‐benzotriazole–3‐nitro­benzoic acid (1/1), C₆H₅N₃·C₇H₅NO₄, (III), imidazol­ium 3‐nitro­benzoate, C₃H₅N₂⁺·C₇H₄NO₄^?, (IV), and imid­azolium 4‐nitro­benzoate, C₃H₅N₂⁺·C₇H₄NO₄^?, (V), were prepared with the aim of making chiral crystals. Only (I) crystallizes in a chiral space group. The mol­ecules of (I) and (II) are linked by hydrogen bonds to form 2₁ spiral chains. In (III), (IV) and (V), macrocyclic structures are formed from two acid and two base components, by an alternate arrangement of the acid and base moieties.     

Synthesis and FET characterization of novel ambipolar and low‐bandgap naphthalene‐diimide‐based semiconducting polymers

A novel series of naphthalene‐diimide‐based semiconducting polymers ( P1–P4 ) containing benzodithiophene or dithienopyrrole were successfully synthesized for ambipolar semiconducting materials showing near infrared absorptions. The incorporation of a 3‐hexylthiophene (3HT) spacer extended the intramolecular charge‐transfer (ICT) peak from λ_onset = 739 nm ( P1 ) to 785 nm ( P3 ). Moreover, about 250 nm red‐shift of the ICT peaks was observed in P2 and P4 compared to P1 and P3 due to the increased high‐lying HOMO energy levels. The grazing incidence X‐ray scattering of the P3 and P4 films proved the slightly improved crystalline order in the π?π stacking direction, indicating that the planar backbone is probably due to the introduced 3HT. The P1–P4 ‐based field‐effect transistor showed n‐type dominant ambipolar characteristics. The P2 and P4 showed higher electron mobilities up to 1.5 × 10^?2 cm² V^?1 s^?1 than P1 and P3 , which might be influenced by the orientation of the polymer backbone and the intermolecular orbital overlap. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 359–367     

Comparison of electrochemical properties of two-component C60-Pd polymers formed under electrochemical conditions and by chemical synthesis

The electrochemical behavior of C₆₀-Pd polymer formed under electrochemical conditions and by the chemical synthesis was examined. In these polymers, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. Both materials deposited at the electrode surface show electrochemical activity at negative potentials due to the reduction of fullerene cage. Electrochemically formed thin polymeric films exhibit much more reversible voltammetric response in comparison to chemically synthesized polymers. The morphology and electrochemical behavior of chemically synthesized C₆₀-Pd polymer depend on the composition of grown solution. Chemical polymerization results in formation of large, ca. 50 μm, crystallic superficial structures that are composed of regular spherical particles with a diameter of 150 nm. The capacitance properties of C₆₀-Pd films were investigated by cyclic voltammetry and faradaic impedance spectroscopy. Specific capacitance of chemically formed films depends on the conditions of film formation. The best capacitance properties was obtained for films containing 1:3 fullerene to Pd molar ratio. For these films, specific capacitance of 35 Fg^?1 was obtained in acetonitrile containing (n-C₄H₉)₄NClO₄. This value is much lower in comparison to the specific capacitance of electrochemically formed C₆₀-Pd film.     

Synthesis and characterization of fused‐thiophene containing naphthalene diimide n‐type copolymers for organic thin film transistor and all‐polymer solar cell applications

Naphthalene diimide copolymers are attractive n‐type materials due to their high electron affinities, high electron mobilities, and exceptional stability. Herein, we report a series of NDI‐fused‐thiophene based copolymers with each copolymer differing in the number of fused thiophenes in the donor monomer. Increasing the number of fused‐thiophene moieties within an NDI‐copolymer backbone is shown to not only enable tuning of the electronic structure but also improve charge mobilities within the active layer of organic field‐effect transistors. Electron mobilities and on/off ratios as high as 0.012 cm² V^?1 s^‐1 and I_on/I_off > 10⁵ were measured from n‐channel thin‐film transistors fabricated using NDI‐xfTh copolymers. Bulk heterojunction solar cell devices were also fabricated from the NDI‐xfTh copolymer series in blends with poly(3‐hexylthiophene) (P3HT) with PNDI‐4fTh ‐ based devices yielding the largest J_sc (0.57 mA cm^?2) and fill factor (55%) in addition to the highest measured PCE for this series (0.13%). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4061–4069     

Formation of Ultrathin,Continuous Metal–Organic Framework Membranes on Flexible Polymer Substrates

Metal–organic framework (MOF) materials have an enormous potential in separation applications, but to realize their potential as semipermeable membranes they need to be assembled into thin continuous macroscopic films for fabrication into devices. By using a facile immersion technique, we prepared ultrathin, continuous zeolitic imidazolate framework (ZIF‐8) membranes on titania‐functionalized porous polymeric supports. The coherent ZIF‐8 layer was surprisingly flexible and adhered well to the support, and the composite membrane could sustain bending and elongation. The membranes exhibited molecular sieving behavior, close to the theoretical permeability of ZIF‐8, with hydrogen permeance up to 201×10^?7 mol m^?2 s^?1 Pa^?1 and an ideal H₂/CO₂ selectivity of 7:1. This approach offers significant opportunities to exploit the unique properties of MOFs in the fabrication of separation and sensing devices.     

Poly(Ferrocenylalkylammonium): A Molecular Electrode Material for Dihydrogenphosphate Sensing

By virtue of strong ion‐paring interactions that are reinforced following oxidation of ferrocene moieties to ferrocenium form, films synthesized by oxidative polymerization of pyrrole‐containing (ferrocenylmethyl)trialkylammonium cations are able to electrochemically sense the dihydrogenphosphate anion in organic electrolytes. Strong and selective affinity of these cationic polymer films towards H₂PO₄^? was evidenced from FT‐IR and EQCM experiments. Clear two‐wave differential pulse voltammetry features allow the amperometric titration of this anion.     

Synthesis of Mesoporous Lithium Titanate Thin Films and Monoliths as an Anode Material for High‐Rate Lithium‐Ion Batteries

Mesoporous Li₄Ti₅O₁₂ (LTO) thin film is an important anode material for lithium‐ion batteries (LIBs). Mesoporous films could be prepared by self‐assembly processes. A molten‐salt‐assisted self‐assembly (MASA) process is used to prepare mesoporous thin films of LTOs. Clear solutions of CTAB, P123, LiNO₃, HNO₃, and Ti(OC₄H₉)₄ in ethanol form gel‐like meso‐ordered films upon either spin or spray coating. In the assembly process, the CTAB/P123 molar ratio of 14 is required to accommodate enough salt species in the mesophase, in which the Li^I/P123 ratio can be varied between molar ratios of 28 and 72. Calcination of the meso‐ordered films produces transparent mesoporous spinel LTO films that are abbreviated as Cxx‐yyy‐zzz or CAxx‐yyy‐zzz (C=calcined, CA=calcined–annealed, xx=Li^I/P123 molar ratio, and yyy=calcination and zzz=annealing temperatures in Celsius) herein. All samples were characterized by using XRD, TEM, N₂‐sorption, and Raman techniques and it was found that, at all compositions, the LTO spinel phase formed with or without an anatase phase as an impurity. Electrochemical characterization of the films shows excellent performance at different current rates. The CA40‐350‐450 sample performs best among all samples tested, yielding an average discharge capacity of (176±1) mA h g^?1 at C/2 and (139±4) mA h g^?1 at 50 C and keeping 92 % of its initial discharge capacity upon 50 cycles at C/2.