19 research outputs found
Synthesis of π-Conjugated Poly(cyclodiborazane)s by Organometallic Polycondensation
Donor−acceptor type π-conjugated poly(cyclodiborazane)s were synthesized by organometallic polycondensation between cyclodiborazane-containing dibromide and 2,5-didodecyloxy-1,4-diethynylbenzene utilizing Sonogashira coupling. The polymerization was carried out under a nitrogen
atmosphere, in THF/NEt3 solution in the presence of a catalytic amount of copper acetate, palladium
chloride, and triphenylphosphine at 80 °C for 12 h. After reprecipitation into MeOH, the resulting polymer
was isolated as a brown powder in moderate yield. The polymer obtained was soluble in common organic
solvents such as THF, chloroform, and benzene, and its structure was confirmed by 1H NMR, 11B NMR,
and IR spectra. The number-average molecular weight of the polymer was 8500 from the gel permeation
chromatographic analysis (GPC, THF, PSt standards). In the UV−vis absorption spectrum recorded in
chloroform, the absorption maximum was observed at 414 nm, owing to extension of π-conjugation via
the vacant p-orbital of the boron atom and intramolecular charge transferred structure. This polymer
exhibited an intense blue-green light emission upon irradiation at 414 nm
Charge–Discharge Behavior of Lithium-Ion Batteries Using a Polymer Electrolyte Bearing High-Density Functional Groups
Lithium-ion batteries (LIBs) have
become crucial for various applications,
but carbonate-based liquid solvents, commonly used in their electrolytes,
suffer from the flammability and exchange dynamic of lithium-ion movement
in electrolytes. To address these issues, polyÂ(ethoxycarbonylmethylene)
(PECM) with a dense distribution of functional ester groups was evaluated
as a polymer electrolyte in LIBs. The polymer was shown to be polar
aprotic with an ET(30) value of 43.85
kcal mol–1 and to offer improved solvation of cations.
Polymer electrolytes (PEs) in combination with LiTFSI showed a glass
transition temperature in the range of 10–33 °C. PEs demonstrated
good ionic conductivity within the range of 9.76 × 10–5–3.08 × 10–4 S cm–1 at 51 °C, lithium-ion transference number between 0.80 and
0.98, and activation energy of diffusion within 27.4–43.0 kJ
mol–1. The PECM-based cathodic half-cell exhibited
good rate capacity at varied current densities, and long-cycle performance
showed 80% capacity retention at 0.2 C for more than 100 cycles. The
effect of polarity on the conductivity and transport number and interfacial
compatibility with the cathode show promise as an alternative electrolyte
material for future lithium-ion battery applications
Extension of π-Conjugation Length via the Vacant p-Orbital of the Boron Atom. Synthesis of Novel Electron Deficient π-Conjugated Systems by Hydroboration Polymerization and Their Blue Light Emission
Extension of π-Conjugation Length via the Vacant
p-Orbital of the Boron Atom. Synthesis of Novel
Electron Deficient π-Conjugated Systems by
Hydroboration Polymerization and Their Blue Light
Emissio
Ï€-Conjugated Poly(cyclodiborazane)s with Intramolecular Charge Transferred Structure
Ï€-Conjugated Poly(cyclodiborazane)s with
Intramolecular Charge Transferred
Structur
Heavy-Duty Performance from Silicon Anodes Using Poly(BIAN)/Poly(acrylic acid)-Based Self-Healing Composite Binder in Lithium-Ion Secondary Batteries
Natural abundance and high theoretical
capacity make silicon a
promising anode material in Li-ion batteries (LIBs). However, repeated
cycling causes the pulverization of Si particles due to the large
volume expansion that results in their rapid breakdown, delamination
from the current collector, loss of electrical contact, and thick
solid–electrolyte interphase (SEI) formation. This results
in their poor performance. To overcome these drawbacks, the application
of functional polymers as binders to silicon anodes has emerged as
a competitive strategy. In this regard, here, the design, synthesis,
and application of a highly robust n-type self-healing polymer composite
polyÂ(bisiminoacenaphthenequinone)/polyÂ(acrylic acid) (P-BIAN/PAA)
as a binder for Si anodes is reported. On its application, P-BIAN/PAA
was evaluated to (i) provide mechanical robustness to the large volume
expansion of Si particles, (ii) maintain electrical conductivity within
the electrode laminate, and (iii) facilitate the formation of a thin
SEI by restricting the extent of electrolyte decomposition on the
surface of anode because of its low-lying lowest unoccupied molecular
orbital (LUMO) that empowers its n-doping in the reducing environment.
As a result, Si anodes could be stabilized for over 600 cycles of
charge–discharge with a high reversible capacity of about 2100
mAh g–1Si, ∼95% capacity retention,
and >99% Coulombic efficiency. The extent of suppression of electrolyte
decomposition that led to a facile and thin interphase-SEI and the
corresponding interfacial components with respective impedance values
were not only theoretically evaluated but also supported by cyclic
voltammetry (CV), electrochemical impedance spectroscopy (EIS), and
dynamic-EIS. Further, the postmortem characterization of the anode
by X-ray photoelectron spectroscopy (XPS) justified the thin SEI formation
on Si anode with P-BIAN/PAA composite binder
Synthesis of Poly(cyclodiborazane)s Bearing a Disilanylene Unit and Their Optical and Electrochemical Properties
Synthesis of Poly(cyclodiborazane)s Bearing
a Disilanylene Unit and Their Optical and
Electrochemical Propertie
Selective Ion Transport in Organoboron Polymer Electrolytes Bearing a Mesitylboron Unit
Selective Ion Transport in Organoboron
Polymer Electrolytes Bearing a Mesitylboron
Uni
Alternating Poly(borosiloxane) for Solid State Ultrasensitivity Toward Fluoride Ions in Aqueous Media
Facile synthesis
of alternating copolymer polyÂ(borosiloxane) via
dehydrocoupling was successfully carried out in the presence of transition
metal catalyst at room temperature. The polymer was characterized
by NMR and IR spectroscopy. The presence of a single peak in <sup>11</sup>B NMR and <sup>29</sup>Si NMR supported the alternating sequence
of the polymer which was further complimented by the study of specifically
designed model reactions. Fluoride ion sensitivity was analyzed by
electrochemical methods.. The anion selective electrode prepared using
synthesized polymer was found to be extremely sensitive toward fluoride
ions (10<sup>–10</sup> M in aqueous media) by potentiometric
measurements using 0.1 M disodium hydrogen phosphate as supporting
electrolyte, Ag/AgCl as reference electrode, and Pt wire as counter
electrode
BIAN-Based Porous Organic Polymer as a High-Performance Anode for Lithium-Ion Batteries
Lithium-ion batteries are heralded
as potential candidates for
large-scale energy storage applications. The low specific capacity
or poor cyclability of commonly used anodes limit the extensive application
of lithium-ion batteries. In this context, organic molecules can offer
a potential solution to extend the scope of lithium-ion battery application.
In this work, we demonstrate the synthesis and electrochemical properties
of a nitrogen-rich, n-type porous organic polymer bearing BIAN and
melamine moieties (PBM). The PBM exhibits a porosity of 1.5 nm and
excellent electrochemical performance in terms of its rate capability,
cycling behavior, and capacity. The anodic half-cell of the PBM active
material delivers specific capacities of 850 mAh/g at 400 mA/g, 740
mAh/g at 750 mA/g, and 300 mAh/g at 1000 mA/g current densities with
an excellent cyclability over 3000, 2000, and 1100 cycles, respectively,
at each current density. Thus, this material is a promising candidate
as an anodic material in lithium-ion batteries
BIAN Based Electroactive Polymer with Defined Active Centers as Metal-Free Electrocatalysts for Oxygen Reduction Reaction (ORR) in Aqueous and Nonaqueous Media
We
report design, synthesis, and performance evaluation of functional
polymer material with defined active sites for oxygen reduction reaction
(ORR) catalytic activity in aqueous as well as nonaqueous media. The
BIAN-paraphenylene (BP) copolymer having an imine backbone was synthesized
via solution based polycondensation. The as synthesized polymer itself
showed ORR activity comparable to that of other doped carbon materials.
The composites of the polymer with graphene oxide (GO) sheets (GO/BP)
were also synthesized under moderate temperature conditions (400 °C)
with the polymer remaining intact. The composites showed further enhanced
electrochemical activity owing to the synergistic effect of GO and
active site defined polymer material. We also tried to evaluate the
nature and basis of catalytic activity on the polymer surface by different
techniques. The cyclic voltammograms showed two distinct ORR peaks,
indicating two different active sites. This was also in agreement
with Mulliken charge distribution from DFT studies, which showed the
presence of two different carbons next to nitrogen having different
electropositive nature