Science Daily January 20, 2022 Lithium–air batteries (LABs) are potential candidates for next-generation rechargeable batteries because of their extremely high theoretical energy density. However, the reported values for the actual energy density of LABs are much lower than those for lithium batteries, mainly due to the excess amount of electrolyte in the cell. In the present review article, researchers in Japan estimated the practical energy density for the representative LABs reported in academia, and the critical factors for improving the energy density of LABs are summarized. The criteria for evaluating LABs in laboratory-based experiments are also proposed for accurately predicting […]
Tag Archives: S&T Japan
Scientists reduce all-solid-state battery resistance by heating
Science Daily January 7, 2022 The interface between the positive electrode and solid electrolyte in an all-solid state battery shows a large electrical resistance, and the resistance increases when the electrode surface is exposed to air, degrading the battery capacity and performance. Researchers in Japan demonstrated that drastic reduction of the resistance is achievable by annealing the entire battery cell. Exposing the LiCoO2 positive electrode surface to H2O vapor increases the resistance by more than 10 times (to greater than 136 Ω cm2). The magnitude can be reduced to the initial value (10.3 Ω cm2) by annealing the sample in […]
Scientists successfully manipulate a single skyrmion at room temperature
Nanowerk December 17, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single skyrmion. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese, Co9Zn9Mn2 to observe the dynamics of a single skyrmion at room temperature. They were able to track the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic transition from a pinned static […]
Tsunamis’ magnetic fields are detectable before sea level change
Phys.org December 21, 2021 The motion of conductive seawater by tsunamis can generate magnetic fields in the presence of the background geomagnetic main field. Previous studies found that, using the tsunami-generated seafloor magnetic field, it is possible to predict the propagation direction and wave height prior to the actual arrivals of tsunamis. In this study researchers in Japan correlate the tsunami magnetic field and the tsunami sea level change using observed data and three-dimensional simulations of the 2009 Samoa and 2010 Chile tsunamis. Their direct comparison of the tsunami observed magnetic field and tsunami sea level change illustrated that the […]
Scientists successfully manipulate a single skyrmion at room temperature
Nanowerk November 24, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single tiny vortex. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese which is known as a chiral-lattice magnet. They directly observed the dynamics of a single skyrmion at room temperature and tracked the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic […]
Towards self-restoring electronic devices with long DNA molecules
Science Daily November 2, 2021 single-molecule conductance falls off sharply with the length of the molecule so that only extremely short stretches of DNA are useful for electrical measurements. Researchers in Japan achieved an unconventionally high conductivity with a long DNA molecule-based junction in a “zipper” configuration that also shows a remarkable self-restoring ability under electrical failure. The team used a 10-mer and a 90-mer DNA strand to form a zipper-like structure and attached them to either a gold surface or to the metal tip of a scanning tunneling microscope. The separation between the tip and the surface constituted the […]
On-water creation of conducting MOF nanosheets
Science Daily October 28, 2021 Researchers in Japan have created functional materials with advanced three-dimensional nanostructures that conduct electricity based on the idea that unique reactions occur at interfaces of water and oil. As they spread a solution containing organic linkers on aqueous solution of metal ions the substances begin assembling their components in a hexagonal arrangement forming nanosheets where the liquid and air meet. They used two barriers to compress the nanosheets into more dense and continuous state. The process produced thin nanosheets with highly organized crystalline structures, tightly ordered crystals also indicated the electrical properties of the material. […]
Stronger than spider silk: Bagworm silk enables strong conducting fibers
Science Daily October 22, 2021 Researchers in Japan combined polyaniline, a conducting polymer that can be easily synthesized, with bagworm silk obtained from a bagworm nest. The composite fibers obtained from the silk and polyaniline were 2 microns in diameter and acted as optical waveguides. They demonstrated that green laser light propagates along these fibers, while remaining confined within each fiber. Using SQUID measurements they determined that the fibers can act as paramagnets. By applying the bagworm silk/polyaniline composite in a field-effect transistor device, the research team also confirmed that the composite fiber is suitable for use in textile transistors. […]
Teaching robots to think like us
Science Daily October 26, 2021 Researchers in Japan have taught a robot to navigate through a maze by electrically stimulating a culture of brain nerve cells connected to the machine. The neurons were grown from living cells and acted as the physical reservoir for the computer to construct coherent signals. The signals are regarded as homeostatic signals, telling the robot the internal environment was being maintained within a certain range and acting as a baseline as it moved freely through the maze. Throughout trials, the robot was continually fed the homeostatic signals interrupted by the disturbance signals until it had […]
All-nitride superconducting qubit made on a silicon substrate
Science Daily September 20, 2021 Researchers in Japan have developed superconducting qubits based on NbN/AlN/NbN epitaxial Josephson junctions on silicon substrates which promise to overcome the drawbacks of qubits based on Al/AlOx/Al junctions. The all-nitride qubits have great advantages such as chemical stability against oxidation, resulting in fewer two-level fluctuators, feasibility for epitaxial tunnel barriers that reduce energy relaxation and dephasing, and a larger superconducting gap of ~5.2 meV for NbN, compared to ~0.3 meV for aluminum, which suppresses the excitation of quasiparticles. By replacing conventional MgO by a silicon substrate with a TiN buffer layer for epitaxial growth of […]