A facile and efficient method was developed to prepare highly stretchable and conductive graphene conductors with wrinkled structures by the mechanical stretching and shrinking of elastomeric substrates, in which graphene inks were printed on a prestretched elastomeric substrate. Stretchable and exfoliated graphene inks were prepared by mixing graphite and Ecoflex in a shear-assisted fluid dynamics reactor. The resultant graphene conductor exhibited excellent stretchability at 150% strain and high electrical conductivity of 64 ± 1.2 S m− 1. The resistance of the conductor did not change in bent, twisted, and stretched states. The resistance did not change during 10,000 cycles of stretching/releasing, with a maximum strain of 150%. Based on the graphene conductor, a stretchable conductometric sensor with a two-electrode configuration was fabricated to measure impedance changes at different concentrations of electrolyte ions. This sensor exhibited a good and linear sensitivity curve (298.61 Ω mM− 1, R2 = 0.999) in bent and stretched states.

Laser induced surface activation (LISA) technology requires refined selection of process variables to fabricate conductive microcircuits on a general polymer material. Among the process variables, laser mode is one of the crucial factors to make a reliable conductor pattern. Here we compare the continuous wave (CW) laser mode with the pulse wave (PW) laser mode through determination of the surface roughness and circuit accuracy. In the CW laser mode, the surface roughness is pronounced during the implementation of the conductive circuit, which results in uneven plating. In the PW laser mode, the surface is relatively smooth and uniform, and the formed conductive circuit layer has few defects with excellent adhesion to the polymer material. As a result of a change of laser mode from CW to PW, the value of Ra of the polymer material decreases from 0.6 m to 0.2 m; the value of Ra after the plating process decreases from 0.8 m to 0.4 m, and a tight bonding force between the polymer source material and the conductive copper plating layer is achieved. In conclusion, this study shows that the PW laser process yields an excellent conductive circuit on a polymeric material.

The anion exchange membrane fuel cells (AEMFCs) have been known to be promising eco-friendly power sources. To develop AEMFCs, the high ion conductivity, good dimensional, mechanical and alkaline stabilities are required for AEMs. However, the high conductivity generally requires high water uptake, which causes an enhanced swelling and decreased mechanical properties for the AEMs. To overcome this problem, we introduced an ionic conductor having long alkyl diammonium groups to alkyl-substituted poly(p-phenylene oxide) (PPO). Addition of this new additive increased the conductivity, mechanical and alkaline stabilities due to the molecular interaction between alkyl chains in PPO and same group of the additive. Synthesis and properties of the corresponding membranes will be discussed in detail.

In development of high speed Rigid conductor line(R-bar) over 250km/h, it is important to develop the method to anticipate the mechanical stability of the R-bar and of the transition structure which connects the flexible Overhead Contact Line. To do this, firstly, the FE(Finite Element) model for a transition structure was established and the initial deformed configurations due to gravitational force is obtained by a static analysis and the pantograph was modeled by a simplified mass-spring-damper system and the contact behavior between conductor and pantograph was defined by the penality method. Secondly, FE analysis results were reviewed with the test results of contact force between conductor and pantograph at the low speed of train. Finally, using the established analysis method, the evolution of contact forces was performed for a newly designed high speed R-bar and for its transition structure.

To observe the bonding structure and electrical characteristics of a GZO oxide semiconductor, GZO was deposited on ITO glasses and annealed at various temperatures. GZO was found to change from crystal to amorphous with increasing of the annealing temperatures; GZO annealed at 200 oC came to have an amorphous structure that depended on the decrement of the oxygen vacancies; increase the mobility due to the induction of diffusion currents occurred because of an increment of the depletion layer. The increasing of the annealing temperature caused a reduction of the carrier concentration and an increase of the bonding energy and the depletion layer; therefore, the large potential barrier increased the diffusion current dna the Hall mobility. However, annealing temperatures over 200 oC promoted crystallinity by the defects without oxygen vacancies, and then degraded the depletion layer, which became an Ohmic contact without a potential barrier. So the current increased because of the absence of a potential barrier.

The electrochemical behavior of the LiCoO2 electrode, containing carbon black as a conductor, depends upon the nature and characteristics of carbon black. In this study, six different kinds of carbon blacks were employed to investigate the relationship between the properties of carbon blacks and electrochemical characteristics of the electrode. The larger amount of surface oxygen functional groups brought the lower electrical conductivity for the carbon blacks. The electrical conductivity of carbon blacks was closely related to the impurities such as ash and volatile content. The rate capability and cyclability of the electrode were improved with the higher conductivity of carbon blacks used. So, it can be concluded that high conductive carbon black plays an important role as a conductor for high rate of charge-discharge capability and initial efficiency.