Stanford team demonstrates a graphene-based thermal-to-electricity conversion technology

Jan 25, 2017

Researchers at Stanford University have recently demonstrated a graphene-based high efficiency thermal-to-electricity conversion technology, called thermionic energy convertor. By using graphene as the anode, the efficiency of the device is increased by a factor of 6.7 compared with a traditional tungsten anode. This technology can work in a tandem cycle with existing thermal-based power plants and significantly improve their overall efficiencies.

Stanford team creates graphene-based TEC image

Hongyuan Yuan and Roger T. Howe, among the leading researchers in the Stanford team, explain that one of the major challenges for wide adoption of TECs is high anode work function, which directly reduces the output voltage as well as the net efficiency. The theoretical maximum efficiency for a TEC with a 2 eV work function anode is 3% at a cathode temperature of 1500 K, compared to an astonishing 10-fold increment to 32% with a 1 eV work function anode.

Crumpled graphene may benefit self-cleaning surfaces and batteries

Mar 22, 2016

Researchers at Brown University have demonstrated that graphene, wrinkled and crumpled in a multi-step process, becomes significantly better at repelling water - a property that could be useful in making self-cleaning surfaces. Crumpled graphene also has enhanced electrochemical properties, which could make it more useful as electrodes in batteries and fuel cells.

The researchers aimed to build relatively complex architectures incorporating both wrinkles and crumples. To do that, the researchers deposited layers of graphene oxide onto shrink films -polymer membranes that shrink when heated. As the films shrink, the graphene on top is compressed, causing it to wrinkle and crumple. To see what kind of structures they could create, the researchers compressed same graphene sheets multiple times. After the first shrink, the film was dissolved away, and the graphene was placed in a new film to be shrunk again.

Seamlessly bonded graphene and CNTs form a 3D material that maintains conductivity

Sep 07, 2015

In a research funded by a U.S. Department of Defense-Multidisciplinary University Research Initiative grant and Wenzhou Medical University, an international team of scientists has developed what is referred to as the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in 3D. The research may hold potential for increased energy storage in high efficiency batteries and supercapacitors, increasing the efficiency of energy conversion in solar cells, for lightweight thermal coatings and more. 

The group's early testing showed that a 3D fiber-like supercapacitor made with uninterrupted fibers of carbon nanotubes and graphene matched or even surpassed bettered the reported record-high capacities for such devices. When tested as a counter electrode in a dye-sensitized solar cell, the material enabled the cell to convert power with up to 6.8% efficiency and more than doubled the performance of a similar cell that used an expensive platinum wire counter electrode. 

Spanish university develops graphene-based catalysts for the energy industry

Aug 27, 2015

Researchers at the Spanish Universitat Jaume I have developed graphene-based materials that can catalyse reactions for the conversion and storage of energy. The technology combines graphene and organometallic compounds in a single material without altering graphene's properties like electrical conductivity.

The technology is expected to be of great interest to the energy industry and is part of what is known as "hydrogen economy", an alternative energetic model in which energy is stored as hydrogen. In this regard, the materials (patented by the UJI) allow catalysing reactions for obtaining hydrogen from alcohols and may also serve as storage systems of this gas.

Israeli and Australian scientists come up with a fast and efficient method of producing graphene

Jul 25, 2015

Researchers at the Israeli Ben-Gurion University of the Negev (BGU) and University of Western Australia have designed a new process for creating few-layer graphene for use in energy storage and other material applications that is faster, potentially scalable and surmounts some of the current graphene production limitations.

The new one-step, high-yield generation process is based on an ultra-bright lamp-ablation method and has succeeded in synthesizing few-layer (4-5) graphene in relatively high yields. It involves a novel optical system (originally invented by BGU professors) that reconstitutes the immense brightness within the plasma of high-power xenon discharge lamps at a remote reactor, where a transparent tube filled with simple, inexpensive graphite is irradiated. The process is considered fast, safe and green (free of any toxic substances - just graphite plus concentrated light).