LG Chem Cable Batteries to Reform Mobile Designs

LG Chem developed cable-type lithium-ion batteries that are so flexible that it can actually be tied in knots, worn as a bracelet, or woven into textiles.

For mobile device designers, the eventual commercial production of such a battery would be a very big challenge in reducing design constraints. Flexible batteries have been created before but made in flat sheets and have not stored much energy. The LG Chem flexible battery is thin, very flexible, and can be placed anywhere in any shape. Thin strands of copper wire are coated with nickel-tin. The strands are made into a metal yarn and wrapped around a rod. Once the rod is removed, a strong spring results.

When LG Chem used a fourth-generation iPod Shuffle for testing, the prototype successfully operated a red LED screen and MP3 player under severe twisting and bending conditions.

When fourth-generation iPod Shuffle was used for testing, the prototype successfully operated a red LED screen and MP3 player under severe twisting and bending conditions.

The goal is to have this battery ready for the mass production. The day may come none too soon for device designers, who would be eager to work with more novel form factors but cannot because of the limitations set by batteries. They think the type of battery that is being developed by the company could potentially alter the device landscape.

The limiting factor in the area of portable electronics is the shape of the battery. In spite of efforts made to develop smaller, thinner and lighter batteries, it does not resolve the constraints owing to the flexibility of the products. 

The LG Chem continues working on intending to test new anode materials, for the batteries to deliver more power, faster.

LG Chem lays claim to being an important force in battery design progress. They began mass production of Korea's first lithium-ion batteries in 1999. By the end of 2008, LG Chem was the fourth-largest maker globally.

Electricity and Plastic Created by Harnessing Waste Water

Treat waste water to create energy and biodegradable plastics

TREATING wastewater is energy intensive. But it does not have to be such a drain on resources; soon it might be able to earn its keep.

A team led by Hong Liu from Oregon State University in Corvallis has plans for microbial fuel cells that will reclaim energy from waste water and produce around 2.87 watts of electrical power per liter of waste water. That is almost double the amount of electrical power usually required for such a cell. Its by-products could be harnessed to create cheap and biodegradable plastics.

Waste water holds huge amounts of energy, bound up in organic molecules, but difficult to access. The Oregon fuel cells run on microbes that would normally digest organic matter to produce water. In a fuel cell, though, isolated from oxygen, that conversion stalls and electrons, which are bundled with protons and oxygen to form water, are pulled away from the microbes by the potential between a cathode and an anode, producing electrical current.

As well as tweaking the mixture of microbes on the electrodes, the Oregon design has also managed to squash far more electrodes into the fuel cell than on previous versions. Liu says her lab aims to scale up the device within the next five years and make it cheaper. The by-products of waste water treatment can be harnessed too. Engineers are working on a way to convert methane into biodegradable plastics.

The dream plastic would be would be made from organic material that are biodegradable and breaks easily. At the moment, Polyhydroxyalkanoate (PHA) seems to be the best bet. But PHA plastics are manufactured by genetically modified bacteria fed on sugars in a process that is both expensive and complex, making it hard to compete with conventional plastics.

So Molly Morse of Mango Materials in California and colleagues are now using methane, another major by-product of treating waste water. Methanotrophs, simple organisms that feed on methane, are much better at converting it into polymers than typical bacteria are at converting sugar into plastics. Methane is pumped into a vat of Methanotrophs harvested from the waste water treatment plant itself - along with a bubbling stream of oxygen and a few other nutrients. The end result is a polymer powder that can be separated from the mass of bacteria and turned into pellets for shaping into commercial plastic products.

Morse envisions that their waste water plastic could be used for all kinds of temporary or disposable applications, ranging from packaging materials to beauty products.

Science - Latest Development

Highly Stretchable and Bio-compatible Material to Replace Damaged Cartilage in Joints Developed

Experts from various fields at Harvard School of Engineering and Applied Sciences (SEAS) have researched and created highly stretchable and tough material that can replace damaged cartilage in human joints.

The new material is a hydrogel, which is a strong hybrid of two weak gels.  It possesses a high degree of flexibility that can stretch to 21 times its original length. It’s extremely tough, self-healing, and bio-compatible attributes pave way to new opportunities being investigated in medicine and tissue engineering.

Conventional hydrogels (network of polymer chains) are very weak and brittle. But these hydrogels are likely to be used for some very challenging applications like artificial cartilage or spinal disks. For a gel to work in those settings, it has to be able to stretch and expand under compression and tension without breaking.

To create a new hydrogel, researchers combined two common polymers. The primary component is polyacrylamide, commonly used in soft contact lenses and as the electrophoresis gel that separates mixed population of DNA and RNA fragments by length in biology labs; the second component is alginate, a seaweed extract that is commonly used to thicken food.

Separately, these gels are both quite weak - alginate, for instance, can stretch to only 1.2 times its length before it breaks. Combined in an 8:1 ratio, however, the two polymers form a complex network of cross-linked chains that reinforce one another. The chemical structure of this network allows the molecules to pull apart very slightly over a large area instead of permitting the gel to crack.

The portion of gel that is alginate consists of polymer chains that make weak ionic bonds with one another, capturing calcium ions (added to the water) in the process. When the gel is stretched, some of the bonds between chains break or unzip, releasing the calcium. As a result, the gel expands slightly, but the polymer chains remain intact. At the same time, the polyacrylamide chains form a grid like structure that bonds tightly with the alginate chains.

So, if the gel forms a tiny crack as it stretches, the polyacrylamide grid spreads over a large area, pulling on the alginate’s ionic bonds and unzipping them. Even with a huge crack, the hybrid gel can still able to stretch 17 times its initial length.

Important thing to note is that the new hydrogel is able to maintain its elasticity and toughness even after stretched multiple times. Only if the gel has given time to relax between stretches, the ionic bonds between the alginate and the calcium can re-zip. In this research, it was demonstrated that the process of healing can be accelerated by increase in ambient temperature.

The researchers suggest using the new hydrogel in places where it may need hydrogels of high stretchability and toughness like in soft robotics, in optics, in artificial muscle, and as a protective covering for wounds.

The research made on the material, its properties, and a simple method of synthesizing it is described in the September 6th issue of Nature.