Very Promising! Zinc-Air Battery Could Hold 300% More Energy Than Lithium-Ion : TreeHugger

Might This Be the One We’ve Been Waiting For?

Not quite as impressive on paper as the lithium-air battery we wrote about (which claimed 10x more energy storage than regular lithium-ion), but it might turn out to be easier to take out of the lab and bring to market. ReVolt Technology, a company based in Staefa, Switzerland, claims that its Zinc-air battery can “store three times the energy of lithium ion batteries, by volume, while costing only half as much,” and unlike other existing air batteries, this one would be rechargeable. It is planning to start by selling small ones for hearing aids and then progressively scale up to portable electronics and electric cars.

zinc air battery chart image

The original design was created at SINTEF, and ReVolt was a kind of spinoff designed to bring the Zinc-air technology to market.

MIT’s Technology Review writes:

Unlike conventional batteries, which contain all the reactants needed to generate electricity, zinc-air batteries rely on oxygen from the atmosphere to generate current. [...]

making them rechargeable has been a challenge. Inside the battery, a porous “air” electrode draws in oxygen and, with the help of catalysts at the interface between the air and a water-based electrolyte, reduces it to form hydroxyl ions. These travel through an electrolyte to the zinc electrode, where the zinc is oxidized–a reaction that releases electrons to generate a current. For recharging, the process is reversed: zinc oxide is converted back to zinc and oxygen is released at the air electrode. But after repeated charge and discharge cycles, the air electrode can become deactivated, slowing or stopping the oxygen reactions. This can be due, for example, to the liquid electrolyte being gradually pulled too far into the pores, Henriksen says. The battery can also fail if it dries out or if zinc builds up unevenly, forming branch-like structures that create a short circuit between the electrodes.

But ReVolt says it has found a way to better control that, and the company’s first products are expected to work for a many hundreds of cycles, which would be good for portable electronics. But electric cars will require something different, and ReVolt is also working on that:

For electric vehicles, ReVolt is developing a novel battery structure that resembles that of a fuel cell. Its first batteries use two flat electrodes, which are comparable in size. In the new batteries, one electrode will be a liquid–a zinc slurry. The air electrodes will be in the form of tubes. To generate electricity, the zinc slurry, which is stored in one compartment in the battery, is pumped through the tubes where it’s oxidized, forming zinc oxide and releasing electrons. The zinc oxide then accumulates in another compartment in the battery. During recharging, the zinc oxide flows back through the air electrode, where it releases the oxygen, forming zinc again.

This would increase energy density, and also increase the number of cycles before degradation (up to between 2,000 and 10,000 according to the company).

This is very promising, but as usual with news from the lab, we’ll have to wait until it hits the market before we can know if it’s really the holy grail…

via Very Promising! Zinc-Air Battery Could Hold 300% More Energy Than Lithium-Ion : TreeHugger.

Clean Water Everywhere: DIY Clay Water Filters

Clean drinking water has always been a major issue in many developing countries, but with the onset of climate change and droughts, this may become a problem for industrialized countries as well. There is a simple solution for clean water: clay. Tony Flynn with the World Vision charity and Potters for Peace have discovered people everywhere can drink clean water with the materials around us.

Tony Flynn, a master potter and scientist, has created a simple to create water purifier out of incredibly simple materials found almost anywhere in the world. The filter is created with clay, organic materials (coffee grinds or rice), water and manure. The straw and rice are mixed in with the clay and water and then fired over some burning manure. The organic materials are burned away during the firing process and create small passages in the filter that allow water, but not pathogens, to pass. This filter effectively removes 96.4-99.8% of E. Coli in water [Source: ANU]. One of these filters can great a liter of drinkable water in only two hours. You can make your own filter by following these steps:

Materials

1. crushed, dry clay

2. organic material(tea leaves, cofffee grounds, or rice hulls)

3. water

4. Cow manure

Instructions

1. Mix in enough water to make a stiff biscuit-like mixture

2. Form a cylindrical pot that has one closed end

3. Dry the pot in the sun

4. Surround the pot with straw and place it in a mound of cow manure

5. Light the straw and then top up the burning manure as required.

6. Filter will be completed in less than an hour.

This invention was purposely not-patented so that everyone could create their own water filters. Other organizations like Engineers Without Borders and Potters for Peace have introduced a similar clay filter designed by Guatemalan chemist Fernando Mazariegos. The filter follows the same idea as the one created by Tony Flynn, but fires the clay inside of a kiln rather than over an open fire and paints the filter with colloidal silver afterwards. The silver helps to remove bacteria and pathogens that traditional clay filters might otherwise miss [Source: Gazette Times].

While clay filters are easy to create and much environmentally friendly, there are some downfalls. One of the major disadvantages is that they can only produce a small amount of water and that if the water is turbid, then the filter needs to be scrubbed after use. This abrasive treatment wears away the ceramic and may even crack the ceramic. Any cracks would allow pathogens to short circuit the filters. Clay filters may be cheap to produce, but if the surface water that they are treating is highly turbid the filters may have a relatively short life [Source: RELFE] and need to be replaced at a very high rate.

Despite these flaws, clay filters are gaining in popularity and countries like Ghana and Cambodia are producing thousands of these for distribution per year. Clean drinking water does not have to a problem in the future if we take precautions not to pollute our water or climate.

via Clean Water Everywhere: DIY Clay Water Filters : Planet Green.

Green Halloween Tips – 4 Stress-Free Ways to Go Green This Halloween

Halloween should be green. From the candy to the costumes to the plastic scary stuff all over lawns, there are plenty of things needing greening.

Here are four cool quick ideas for a green Halloween.

1. Recycle old costumes or plastic scary things you leave on your lawn from years past. That should have been done anyway. If you don’t need to go out and buy something why should you? That reduces consumption.

2. Use eco-friendly face paints. Your local health food store or chain like Whole Foods or Mrs. Greens ought to have something for you.

3. Give away wholesome treats. My kids love Halloween for the sugar rush, so at least make it organic or fair trade. Or give something a bit healthier; then you really are giving a treat, not a trick for parents to deal with later.

4. Use LED Halloween lights. LEDs are much more efficient than incandescent bulbs and will reduce your expenses for this holiday in the long run. LEDs last a lot longer than CFL or regular bulbs, so you can light up your home and not scare yourself with the electric bill later in November.

via Green Halloween Tips – Cheap Halloween Ideas – Easy Halloween – thedailygreen.com.

Natural Fall Decorations

Instead of plastic seasonal decorations, look for gorgeous natural materials. Also see great homemade costume ideas.

Instead of garish plastic witches, polystyrene pumpkins and cheap Halloween toys that may be contaminated with lead paint, decorate for the fall holidays with natural materials such as gourds, pumpkins and dried corn, leaves and grasses.

By avoiding all that unnecessary plastic and foam, you’ll be saving nonrenewable petroleum for other uses. Instead of something that takes hundreds of years to break down in the environment, you’ll end up with material that can be easily composted in your own yard, returning nutrients to the soil. Between 1960 and 2003, plastics surged from 1% to 11.3% percent of our waste stream, and more and more products are made from the stuff every day.

By choosing natural materials to accent your home or office, you’ll also be supporting American farmers and open space, as well as bringing a little slice of nature (not to mention history) indoors. The best choice is locally sourced goods, which you can pick up at a farmers’ market, farm stand or charity drive. As with the concept of food miles, you’ll be cutting down on the fuel needed to transport items from field to table, leaving Mother Nature smiling like a jack-o-lantern.

via Natural Fall Decorations – Gourds – Halloween Decorations – thedailygreen.com.

Television Energy – How Much Electricity Do TVs Use

How Much Energy Does Your TV Really Use?

3 things to consider before buying your next television (unless, that is, you want to spend hundreds of extra dollars).

“AMan watching a plasma tv. A 42-Inch Plasma TV Can Use As Much Energy as a Refrigerator”

About four years ago I started noticing that flat-panel, big-screen TVs started to pop up almost everywhere I went. Places like the hotel lobby, the fitness center, restaurants, at the airport and increasingly in our friends’ homes. Also overnight, the size of TVs seemed to almost double.

As an energy efficiency advocate I had to know the answer to the question, “How much energy do these new LCD and plasma TVs really use?” Much to my surprise, there was virtually no public information available about their energy use or cost to operate. The only thing out there was the number on the back of the TV that indicates how much power a TV can safely draw before it becomes unsafe to operate.

Not to be deterred I worked with our consultant Ecos Consulting to measure the power use of the latest TVs. We went into a few big box stores armed with a power meter and a two-minute clip of the movie Shrek and measured the power draw of the TVs that were on display. To make a long story short, here is what we found:

• Some of the bigger, less efficient models consumed more electricity each year than a new refrigerator and can cost several hundred dollars to operate over their 10-year life.

• There was a wide range of energy use between similar-sized models. In general, plasmas consumed considerably more energy than equivalent LCD models.

• TVs now represent approximately 5% of U.S. residential electricity use and over 1% of all national electricity use.

I have since dedicated much of the last few years to moving the industry toward more efficient designs. The potential dividends are enormous and include cutting our nation’s electric bill by up to $10 billion a year, eliminating the need for several large power plants, and preventing millions of tons of carbon dioxide, the main heat trapping pollutant responsible for global warming.

And I’m excited to say that my home state of California will lead the way on this one.

via Television Energy – How Much Electricity Do TVs Use – Energy Star Televisions – thedailygreen.com.