2017年3月21日星期二

China Developed Electrochromic Battery Uses Tungsten Oxide

Recently, China has developed a high-capacity, fast charging electrochromic battery. In this type of battery, tungsten oxide (WO2.72, i.e. violet tungsten oxide) nano-wires are taken as a positive electrode, and the metal aluminum is as the negative electrode; compared with other batteries, this kind of cell has some new advantages in the following aspects:

1. It establishes a capacity to identify of interface with the users through color changing, which the specific performance is: the transparent state on behalf of the full status of the battery; when it gradually turns to blue, it means the storage power starts to consume; and when the color reaches the deepest, it says the power is depleted;
2. By adding a trace amount of hydrogen peroxide, it can realize fast charging (full charged within 8s), besides, the traditional external power supply can be used for charging, and also the oxygen in the air can be used to achieve self-charging;
3. The battery capacity is six times (or more) higher than the similar battery.

tungsten trioxide and graphene photo
Electrochromic refers to the optical properties of the material (reflectance, transmittance, absorption rate, etc.) occurs stable and reversible of the phenomenon of color changing under the applied electric field, and it appears in the reversible changing of color and transparency. Electrochromic material is divided into non-organic electrochromic material and organic electrochromic material, wherein the typical non-organic electrochromic material is tungsten trioxide. Violet tungsten oxide is a kind of functional nano material with many properties, such as photochromic, 
electrochromic and gasochromic, it has broad applications in a variety of sensitive element; at the same time, it is one kind of better and more economical method for preparing nanoscale and ultrafine tungsten powder. The violet tungsten oxide usually comes from the raw material of ammonium paratungstate, to generate by controlling the specific reaction conditions.

We all know that the battery capacity is one of the important performance indicators of the battery, with the increasing of the capacity of the battery, the charging time will also be doubled. Of course, in the face of "black technology", this is not a problem, with the rise of all kinds of fast charge technology, the charging time is considerably reduced. The electrochromic battery invented by China, which uses tungsten oxide as a positive electrode, has opened up a new path for the future development of battery.


If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797

Tungsten Oxide Thin Film Electrode Oxidation Glucose

Glucose exists in the nature by photosynthesis. Due to its abundant volume, low cost and reproducible, it is regarded as the main energy substrates to produce hydrogen. Glucose is the main waste of agriculture, food and paper-making industry, improper disposition will cause damage to environment. Recently many PEC systems produce hydrogen by glucose.

Tungsten oxide connects with electrocatalyst to produce hydrogen from glucose shows good photocatalytic activity, deposit electrocatalyst on the surface of photocatalyst can promote photocatalytic activity of semiconductor. Electrocatalyst deposited on the surface of semiconductor will form a layer of cover. By changing electron distribution in the system, the surface property of WO3 will be affected, so the photocatalytic activity is improved. Usually if Fermi level of WO3 is higher than the two combined material, electron will keep migrating from WO3 to depositing electrocatalyst. The shallow well potential Schottk energy barrier which can trap electron will form on the surface of metal and electrocatalyst. It provides effective trap potential for separating of photo electron and electron hole, it can resist the composite of photo electron and electron hole further, also the separating efficiency of charge carrier, thus to improve the quantum efficiency of photocatalyst.

Use FTO/WO3/Ni(OH)2 thin film electrode in reduction of glucose experiment. Through this experiment, we can find that exposure of WO3 thin film electrode without Ni(OH)2 barely have photoelectrocatalytic glucose effect. Depositing Ni(OH)2 on the surface of tungsten oxide thin film can enhance photoelectric effect. Below is the raman spectrum and ultraviolet visible light absorption curve comparison of FTO/WOthin film electrode and FTO/WO3/Ni(OH)2.
WO3 NiOH UV lightWO3 NiOH2 raman spectrum


If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797

Defect State Nano Structure Tungsten Oxide Catalyst Is Invented

USTC(University of Science and Technology of China) recently announced that professor Xiong Yujie research group designed a kind of tungsten oxide nano structure in defect state based on inorganic solid accurate preparation of chemical and use crystalline defect project. Under broad spectrum illumination, it shows fine oxidation coupling catalytic property which is expected to realize low cost and low-energy organic chemical technology. Tungsten oxide has good photocatalytic property due to its special structure, it has already been used as varies of catalyst and also other industrial fields. 

Most of catalytic reaction is based on the application of precious metal oxide and motivated by burning of petroleum and coal. It has disadvantages of high cost and high energy consuming. Compared to precious metal catalyst, metal oxide has benefits of low cost. However, it shows shortcomings in oxygen molecular system which can not capture solar energy and pass it into oxygen molecular.

Defect Rich WO3 Nanosheet Photo

In order to solve the problem, Xiong Yujie research group designed a kind of nano structure tungsten oxide. Usually metal atom of metal oxides has coordination saturation property, it can not active oxygen molecular by chemical absorption. During the research, construct of oxygen vacancy defect overcomes the shortcomings and accelerate photo electron transact from metal oxides catalyst to oxygen molecular. Defect state also broadens light absorption range of photocatalyst which enables it to capture solar energy in visible light and near infrared area. The two big steps realize the valid capture of solar energy and energy transaction, solves the bottleneck problems of oxides catalyst in the organic synthesis of photocatalytic activity.

Based on this acknowledgement, researchers are able to adjust solar energy to drive organic oxygen coupling reaction based on crystalline defect project. It provides possibility to use solar energy take place of heat source organic synthesis, and make an improvement for design of photocatalyst material.


If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797

Nanoporous Tungsten Oxide Making Flexible Memories Device at Room Temperature

Researchers in the US and Korea say they have developed a new way to make a flexible, resistive random access memory (RAM) device in a room-temperature process – something that has proved difficult to do until now. 

The device, which is based on nanoporous tungsten oxide, is a bipolar switch and has a high on/off current ratio of more than 105. It can also be bent and unbent over 103 cycles without suffering any significant loss in performance.

For more than half a century, silicon-based complementary metal-oxide-semiconductor (CMOS) transistors have been the uncontested leaders in the electronics memory industry. However, such memory is reaching its fundamental limits because it is difficult to make CMOS transistors any smaller using current technology – something that will be a drawback for next-generation nanomemory applications. These memories are also quite expensive to assemble and suffer from relatively low switching speeds (of a few microseconds).

Researchers have thus been busy looking for other oxide-based alternatives to CMOS transistors and the most promising of these appear to be the transition metal oxides thanks to their excellent resistive switching characteristics, flexible stoichiometry and compatibility with CMOS processes. Tungsten oxides (WO3-x ) are one of the best transition metal oxides in this context, but the problem is that these materials need to be annealed at high temperatures or plasma treated to improve their quality. Such treatments are not compatible with those used to produce flexible electronics on plastic substrates.
WO3 Memory Device Photo

Electrochemical Anodic Treatment
A team led by James Tour of Rice University in the US recently developed a room-temperature electrochemical anodic treatment to convert metal thin films to metal oxide layers. The researchers have now prepared a nanoporous WO3-x layer on a 175 µm flexible PET substrate using its technique. Anodization is an electrochemical etching process that creates a porous oxide layer on the surface of a metal. The process is called anodizing because an anodic current or voltage is applied to the working electrode in an electrochemical cell.



The nanoporous WO3-x layer thus produced can be used as the active layer in a RRAM device and the researchers have demonstrated this by making a flexible copper/nanoporous WO3-x /ITO memory device on a PET substrate. The device is bipolar with an on/off current ratio of more than 105. What’s more, it continues to operate after being bent and unbent over 1000 times without suffering from any serious switching failure.


If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797

Tungsten Oxide Thermal Metamaterial Innovation Helps Bring Waste-heat Harvesting Technology to Power Plants

An international research team has used tungsten oxide thermal metamaterial to control the emission of radiation at high temperatures, an advance that could bring devices able to get efficient waste-heat harvesting technology from power plants and factories. Roughly 50 to 60 percent of the energy generated in coal and oil-based power plants is wasted as heat. However, thermophotovoltaic devices that generate electricity from thermal radiation might be adapted to industrial pipes in factories and power plants, as well as on car engines and automotive exhaust systems, to recapture much of the wasted energy. In new findings, researchers demonstrated how to restrict emission of thermal radiation to a portion of the spectrum most needed for thermophotovoltaic technology.

thermal metamaterial image

"These devices require spectrally tailored thermal emission at high temperatures, and our research shows that intrinsic material properties can be controlled so that a very hot object glows only in certain colors," said Zubin Jacob, an assistant professor of electrical and computer engineering at Purdue University. "The main idea is to start controlling thermal emission at record high temperatures in ways that haven't been done before." The thermal metamaterial – nanoscale layers of tungsten oxide and hafnium oxide – was used to suppress the emission of one portion of the spectrum while enhancing emission in another.

The basic operating principle of a photovoltaic cell is that a semiconducting material is illuminated with light, causing electrons to move from one energy level to another. Electrons in the semiconductor occupy a region of energy called the valence band while the material is in the dark. But shining light on the material causes the electrons to absorb energy, elevating them into a region of higher energy called the conduction band. As the electrons move to the conduction band, they leave behind "holes" in the valance band. The region between both bands, where no electrons exist, is called the band gap.

Future research will include work to convert heat radiation from a thermal metamaterial to electron-hole pairs in a semiconducting material, a critical step in developing the technology. The thermophotovoltaic technology might be ready for commercialization within seven years, Jacob said.


If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797

Tungsten Oxide As New Material Can Boost Waste Heat Harvesting

A new material that emits short-wavelength thermal radiation when heated could be used in systems that convert waste heat into electrical energy thus boosts waste heat harvesting. Created by an international team co-led by researchers at Purdue University, the University of Alberta and Hamburg University of Technology, the material comprises alternating layers of 20 nm of tungsten oxide and 100 nm of hafnium oxide.

Tungsten oxide is a chemical compound containing oxygen and the transition metal tungsten. It is obtained as an intermediate in the recovery of tungsten from its minerals. Tungsten ores are treated with alkalis to produce WO3. It is insoluble in H2O and acids, but soluble in hot alkalis. It is n type semiconductor material, the special physical and chemical property make it used in various filed and become the important functional material in modern scientific research.

tungsten oxide photo

The structure was chosen so that the emission of long-wavelength infrared photons from the material is suppressed while the emission of shorter wavelength photons is enhanced. These shorter wavelength photons have enough energy to drive a photovoltaic cell, while the longer wavelength photons do not. The research team tested the material by heating it to 1000˚C and using it to power a photovoltaic cell. They found that the new material produced 90% more electrical energy than a conventional black-body infrared emitter. It could someday be used to generate electricity from the waste heat produced by industrial processes and even automobile engines.

If you have any inquiry of tungsten oxide, please feel free to contact us:
Tel.: +86 592 5129696      +86 592 5129595
Fax: +86 592 5129797