•Li4Ti5O12 particles were synthesized with very thin graphene-like sheets in situ coating.•Liquid-polyacrylonitrile was used as the carbon source to form graphene-like coating sheets.•Li4Ti5O12 particles were prepared by the solid ball-milled method.•LTO-1%CB-20%LPAN own high specific capacity and excellent cycling stability at high rate.Li4Ti5O12 particles are synthesized coated with very thin graphene-like sheets in situ using liquid-polyacrylonitrile (LPAN) as the carbon source and added utilized conductivity additives to improve the conductivity of the electrode materials. The crystalline structures of Li4Ti5O12 with 20% LPAN and different conductivity additives composites were examined by XRD. The structure and electrochemical performance of the graphene-like sheets coated Li4Ti5O12, with conductivity additives added, was systematically investigated. The electrochemical performance also revealed that the graphene-like sheets significantly improved the discharge capacity and cycling stability of Li4Ti5O12. In particular, the coated Li4Ti5O12 with 20 wt% LPAN and 1% acetylene black (CB) reached 166.2 mAh g−1 at 10C. The performance improvement is a result of the graphene-like nanosheet conformal coating, which creates an electrically conductive network for the electrode.

Non-noble-metal catalysts have shown promising oxygen reduction reaction (ORR) activity in proton exchange membrane fuel cells (PEMFCs). Herein, by using sulfur-terminated fluidic acrylonitrile telomere (ANT) as precursor, an N and S dual-doped Co/ANT/C catalyst was prepared via a facile heat treatment of the mixture of Co salt, ANT and carbon black, in which cobalt salt was uniformly-dispersed and interacted with ANT. As such, the increasing contact area between ANT and cobalt salt leads to a highly catalytic activity toward oxygen reduction reaction. Most importantly, by using ANT as precursor, the catalyst showed a remarkable improvement in the onset potential and current density as compared with those prepared from pure carbon black, cobalt salt/C or catalyst using high molecular weight polyacrylonitrile as precursor. Besides, the as-made Co/ANT/C catalyst demonstrated a comparable catalytic activity with commercial expensive Pt/C at high loading. In addition, the catalyst participated promotes a direct four-electron reduction of O2 to H2O and long term operation stability in an alkaline medium. Owing to its superb ORR performance, low cost and facile synthesis approach, such prepared Co/ANT/C catalyst has great potential applications in PEMFCs.

Ordered mesoporous carbon (OMC) was synthesized by nano-casting method using novel fluidic precursor – acrylonitrile telomer (ANT). By the penetration of mesoporous silica template with pure ANT, followed by the stabilization, carbonization and removal of the template, we obtained highly ordered mesoporous carbon rods (specific area 408 m2 g−1). When an acetone solution of ANT (66 and 33 wt.%) was used instead of pure ANT, carbon materials with mesopore ranging from 2 to 7 nm were obtained (specific area 843 and 1012 m2 g−1 respectively). Both nitrogen and sulfur atoms were doped into mesoporous carbon with 4 and 0.6 at.% using nitrogen containing monomer and sulfur containing chain transfer agent, without involving complicated synthetic technique and poisonous gaseous compounds. This method was proved to be a facile way to synthesize nitrogen and sulfur containing OMC with partially controllable pore distribution and morphology. More importantly, due to unique mesopore structure and heteroatom doping, Pt nano-particles deposited on the OMCs showed electrocatalytic activity as high as 508 mA mg−1 Pt in methanol oxidation which is 1.7-fold of activity of Pt deposited on commercial Vulcan carbon black.

•A low-temperature thermal stabilization method was first reported for the preparation of CFs.•Cyclization in the amorphous phase and oxidation reactions occurred during the low-temperature thermal stabilization.•The disorientation of PAN molecules was restricted due to the cyclization and oxidation reactions.•Microvoid defects of CFs were reduced with the low-temperature thermal stabilization method.•The mechanical properties and char yield were improved with the low-temperature thermal stabilization method.This article describes a low-temperature thermal stabilization method, for the efficient preparation of polyacrylontrile (PAN)-based carbon fibers with improved mechanical properties. In this method, bundles of regular PAN precursor fibers were firstly heated and stored in air for 30 days at 120 °C to cyclise the nitrile groups and oxidize the PAN backbone. A further stabilization above 200 °C in air made the pretreated fibers fully stabilized. Structural changes of the as-made PAN fibers were observed by Fourier Transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetry and dynamic mechanical analysis. Microvoid evolutions of the fibers during stabilization and carbonization process were studied by synchrotron small-angle X-ray scattering. Our results showed that the initiation of the cyclization and oxidation reaction at 120 °C not only restricts the disorientation of PAN molecules but also reduces the pyrolysis of molecular chains at higher temperatures in the carbonization process. Hence, preferred orientation of crystallites and char yield increased. Moreover, microvoid defects were significantly reduced, leading to a significant improvement of the mechanical properties (a 16% increment in the tensile strength).

Carbon coating is an effective approach to improve the cycling stability of silicon (Si) anodes for lithium-ion batteries. In this research, we report a facile one-step carbon-thermal method to coat Si nanoparticles with nitrogen-doped (N-doped) graphene-like nanosheets derived from a liquid-polyacrylonitrile (LPAN) precursor. The coated Si anode displays an initial coulombic efficiency of 82%, which is about three times greater than its pristine counterpart, as well as superior cycling stability. The performance improvement is a result of the N-doped graphene-like nanosheet conformal coating, which not only creates an electrically conductive network for the electrode, but also provides a buffering matrix to accommodate the volume change of Si during charging and discharging processes.

•Spinel LiMn2O4 in-situ coated with graphene-like membrane is prepared successfully.•Graphene-like membrane is coated on surface of particle, without affecting crystal structure.•Graphene-like membrane improves the electrochemistry performance of spinel LiMn2O4.•Graphene-like membrane does not influence the insertion and desertion of Li+.•Improved electrochemical performance is attributed to in-situ coating of graphene-like membrane.In recent years, modifying cathode materials' surfaces become a popular pursuit. This paper reveals a novel spinel LiMn2O4 in situ coated with graphene-like membrane prepared using liquid-polyacrylonitrile (LPAN) as the carbon source. The structure and electrochemical performance of graphene-like membrane-coated spinel LiMn2O4 are investigated systematically. The membrane has a typical graphene-like layer carbon structure that can be applied the LiMn2O4 particles' surfaces in situ without affecting their crystal structure. Moreover, the graphene-like membrane helps to increase the particle size. The electrochemical performance reveals that coating the graphene-like membrane in situ significantly improves the discharge capacity and cycling stability of the spinel LiMn2O4. In particular, the spinel LiMn2O4 coated with a calcined 20 wt% LPAN graphene-like membrane in situ reached 131.1 mAh g−1 at room temperature, and up to 96% capacity is retained after 50 cycles at 0.1 C. The cyclic voltammetry and electrochemical impedance spectra analyses indicate that the graphene-like membrane does not influence the insertion or desertion of Li+. The improved electrochemical performance is attributed to the decreased manganese dissolution in the electrolyte and the smaller charge transfer resistance generated by the graphene-like membrane coating.

•Li-rich layered Li[Li0.1Ni0.45Mn0.45]O2 coated with graphene-like carbon is prepared.•Graphene-like carbon is prepared by using liquid-polyacrylonitrile.•Graphene-like carbon improves the electrochemical performance of cathode materials.•The discharge capacity of cathode materials can reach 210mAh g−1 at 0.1 C.•The capacity retention of cathode materials is close to 100% after 50 cycles at 0.1 C.This paper reveals a novel Li-rich layered cathode material Li[Li0.1Ni0.45Mn0.45]O2 in situ coated with graphene-like carbon prepared by using liquid-polyacrylonitrile (LPAN) as the carbon source. The structure and electrochemical performance of graphene-like carbon coated Li[Li0.1Ni0.45Mn0.45]O2 are investigated systematically. The results demonstrate that the graphene-like carbon are in situ coated tightly on the surface of Li[Li0.1Ni0.45Mn0.45]O2 particles. The in-situ coating of graphene-like carbon significantly improves the electrochemical properties of cathode materials. The discharge capacity of cell made of 12wt% LPAN-coated Li[Li0.1Ni0.45Mn0.45]O2 can reach 210 mAh g−1 and the capacity retention is close to 100% after 50 cycles at 0.1C. The cyclic voltammgram and electrochemical impedance spectra analyses further demonstrate that the improved electrochemical performance of LPAN-coated Li[Li0.1Ni0.45Mn0.45]O2 cathode materials is attributed to the graphene-like carbon in situ coating, which can protect the cathode directly contact with the electrolyte. Therefore, the Li-rich layered Li[Li0.1Ni0.45Mn0.45]O2 in situ coated with graphene-like carbon is a very good promise cathode material for advanced LIB with high capacity and good stability.

Small angle X-ray scattering and molecular dynamics simulation were used to study the microvoid evolution in carbon fibers (CFs) during tensile deformation. The stress–strain relation and the parameters of microvoids, such as the length, diameter, orientation angle and relative volume were measured. The results demonstrated that during the tensile deformation of CFs, (1) the microvoid volume increased gradually; (2) the microvoid orientation angle with respect to the fiber axis decreased; (3) the mean microvoid length statistically decreased; (4) the short range structure did not change while the bond length of partial C–C increased and the medium and long range structure became disordered; (5) the angle of partial C–C–C shifted to the small angle; (6) the increase of bond lengths and decrease of bond angles mainly appeared at stress concentration areas which were the key damage points. It was indicated that reasonable control of small microvoid growth and stress release could improve the performance of CFs.

Carbon coating is an effective approach to improve the cycling stability of silicon (Si) anodes for lithium-ion batteries. In this research, we report a facile one-step carbon-thermal method to coat Si nanoparticles with nitrogen-doped (N-doped) graphene-like nanosheets derived from a liquid-polyacrylonitrile (LPAN) precursor. The coated Si anode displays an initial coulombic efficiency of 82%, which is about three times greater than its pristine counterpart, as well as superior cycling stability. The performance improvement is a result of the N-doped graphene-like nanosheet conformal coating, which not only creates an electrically conductive network for the electrode, but also provides a buffering matrix to accommodate the volume change of Si during charging and discharging processes.