Energy Harvesting & Storage Tech Digest - May 2017

Hydrogen generating device

A collaboration between the University of Antwerp and KU Leuven, both in Belgium, has developed a light activated device, known as an all-gas-phase photoelectrochemical (PEC), that can purify air and generate hydrogen – that could be later used to generate power – while so doing. The PEC is composed of two chambers separated by a membrane of specially selected nanomaterials that enable the production of hydrogen gas in one chamber when air is purified in the other. The hydrogen can then be stored and converted into power at a later time. The team plans to scale up the device which is only a few centimetres square. 

Ion powered pacemaker

Scientists from UCLA (University of California, Los Angeles) and the University of Connecticut, USA, have developed a pacemaker that uses a biological supercapacitor which captures and stores ions from fluids in the human body. The supercapacitor charges using electrolytes from biological fluid such as blood serum and urine.  The scientists say it would also work with other energy harvesters that convert body-produced heat and motion into electricity, with the supercapacitor capturing the electricity. The supercapacitor is composed of a graphene electrode and is biocompatible.

Self-powering sensor

Scientists at Korea’s Ulsan National Institute of Science and Technology (UNIST) and Korea University have developed a self-sustaining sensor that can simultaneously harvest energy from a water droplet and analyse water dynamics. The system uses a water-contact triboelectric nanogenerator (WC-TENG) that provides power to a self-sustaining water-motion-sensing (SS-WMS) platform that analyses the water movement, converts it into binary and displays the data through LEDs. 

New cathode manufacturing method promises longer life batteries

Researchers at the University of Illinois, Xerion Advanced Battery Corporation and Nanjing University in China have developed a method for electroplating lithium-ion battery cathodes that that could lead to flexible, solid-state batteries. To construct the new cathode the team directly electroplated lithium materials onto aluminium foil, bypassing the traditional manufacturing method of using powder and glue in conventional batteries that takes up space but doesn’t contribute to the functionality of the battery. Not having glue in the new cathode allows for 30% more space in the battery, according to the scientists, who also assert that this method also allows for faster charging and discharging and is more stable than conventional lithium ion batteries.  

Where rivers meet the sea there be electricity

Researchers from Penn State University, USA, have developed a technology that combines several existing methods of generating electrical power from the interaction of seawater and freshwater. The team combined reverse electrodialysis (RED) and capacitive mixing (CapMix) methods – neither of which produce enough electricity to be commercially viable – to create an electrochemical flow cell. The cell consists of two channels separated by a membrane that separates substances based on their charges. A copper hexacyanoferrate electrode was then positioned in each channel and graphene foil was used to collect current. Each tunnel is fed with either saline or non-saline water. Electrical current is created by saltwater going to the electrodes, and also by the chloride crossing the membrane. The power produced has reached 12.6 watts per square metre which is relatively higher than RED and PRO (another similar method) power production at 2.9 and 9.2 watts per square metre respectively.  

Self-healing material could mean longer lasting anodes

University of Illinois researchers have developed a lithium-ion battery that uses self-healing technology to become more reliable and longer lasting. The battery uses a silicon nanoparticle composite material on the anode which, when compared to the currently favoured graphite particle composite, provides higher capacity but it does break down and pulverise after a few charge cycles. The Illinois scientists refined the silicon anode by enabling a reversible chemical bond between the silicon nanoparticles and the polymer binding. This bonding process prevents the anode from breaking apart as easily as previously. Testing of the anode showed that it retained 80% of its capacity after 400 cycles. 

Energy scavenging Tego

Tego is an American company based in Massachusetts that makes RFID (radio frequency identification) devices that scavenge ambient radio wave energy. The RFID devices Tigo produces transform the carrier signal of the RFID reader into a direct current voltage. The power created – which can be as small as 4 milliwatts – can then be used to power the processor in the RFID chip. Tigo’s RFID chip and antenna enables writing, reading and encryption of data. 

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