Flexible graphite film with laser drilling pores as novel integrated anode free of metal current collector for sodium ion battery

In this work, flexible polyimide graphite films with laser drilling pores were prepared by laser drilling pore technique. Then a full cell was built based on the porous graphite film anode, Na3V2(PO4)3 cathode, and NaPF6 in diglyme electrolyte. This unique battery system makes the best of co-intercalation mechanism of Na+-solvent into porous graphite film host. Moreover, the porous graphite film is directly served as an integrated anode with no electrochemically inactive components, such as binders, conductive agents and metallic current collectors. The above merits allow remarkable progress in electrochemical performance, especially the high energy density and much improved cycle life, which will significantly boost the high energy batteries. Our sodium-ion system is potentially promising power sources for promoting the substantial use of low-cost energy storage systems. Keywords: Porous graphite film, Laser drilling pores, Anode, Sodium ion battery, Co-intercalatio

First-principles calculations of diamond/copper (silver, titanium carbide) interface properties

The structure, electrical structure, and heat transmission of diamond/copper, diamond/silver, and diamond/titanium carbide surfaces have been investigated using first-principles calculations. The results show that the diamond/titanium carbide interfacial structure is the most stable, with the shortest interfacial distance (1.990 Å), the greatest interfacial adhesion effort (5.578 J/m2), and the best bond strength. The results of the electronic density of states, mulliken population analysis ,charge density difference, and radial distribution function indicate the presence of more charge transfer and stronger bonding in diamond/titanium carbide. According to the results of the phonon density calculation, the interfacial thermal resistance of diamond/titanium carbide is low

Carbon nanotubes/carbon paper composite electrode for sensitive detection of catechol in the presence of hydroquinone

The fabrication and application of carbon nanotubes/carbon paper (CNTs/CP) composite electrochemical sensors are reported. This sensing platform allows the sensitive determination of catechol in the range of 1 μM to 100 μM with a detection limit of 0.29 μM. The catechol detection in tea samples demonstrates the applicability of this method. The present study explores an interesting and significant application of CNTs/CP composite in electroanalysis. Keywords: Carbon nanotubes/carbon paper, Electrochemical sensor, Catechol, Tea sample

Anticorrosive flexible pyrolytic polyimide graphite film as a cathode current collector in lithium bis(trifluoromethane sulfonyl) imide electrolyte

Flexible pyrolytic polyimide graphite film (PGF) is explored as a cathode current collector in lithium ion batteries using lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) based electrolyte. It is demonstrated that no obvious anodic current is observed up to 4.5 V versus Li+/Li for PGF, while significant corrosion current is found from 3.6 V for aluminum, indicative of better electrochemical stability of PGF than that of aluminum in LiTFSI based electrolyte. LiMn2O4 on aluminum and PGF has been used as model electrode for testing. There is hardly any capacity retained after 10 cycles at room temperature for the LiMn2O4/aluminum electrode. With regard to the LiMn2O4/PGF electrode, the capacity retention ratio remained 89% after 1000 cycles. Moreover, at an elevated temperature of 55 °C, the capacity retention ratio kept at 81% after 300 cycles. Since LiTFSI-based electrolyte shows advantages in safety, stability and conductivity but could not be used due to Al-corrosion, the application of the PGF current collector could overcome this barrier. Keywords: Polyimide graphite film, Current collector, Lithium bis(trifluoromethane sulfonyl) imide, Lithium ion batterie

Coaxial Ni_<i>x</i>Co_2<i>x</i>(OH)_6<i>x</i>/TiN Nanotube Arrays as Supercapacitor Electrodes

Ni_<i>x</i>Co_2<i>x</i>(OH)_6<i>x</i>, as a precursor of intensively studied NiCo₂O₄, has been directly deposited into self-standing titanium nitride nanotube array (TiN NTA) grid monolithic supports to form a coaxial nanostructured electrode for supercapacitors. With TiN NTA substrates providing a large surface area, fast electron transport, and enhanced structure stability, this Ni_<i>x</i>Co_2<i>x</i>(OH)_6<i>x</i>/TiN electrode exhibits superior pseudocapacitive performance with a high specific capacitance of 2543 F g^–1 at 5 mV s^–1, remarkable rate performance of 660 F g^–1 even at 500 mV s^–1, and promising cycle performance (about 6.25% capacitance loss for 5000 cycles). Interestingly, the Ni_<i>x</i>Co_2<i>x</i>(OH)_6<i>x</i>/TiN NTA electrode outperforms the NiCo₂O₄/TiN NTA electrode, indicating that this self-standing Ni_<i>x</i>Co_2<i>x</i>(OH)_6<i>x</i>/TiN NTA monolith is a promising candidate for high-performance supercapacitor applications