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Sony Creating Sulfur-Based Batteries With 40% More Capacity Than Li-Ion (hothardware.com)
MojoKid writes: Since the original iPhone was released in 2007, we have seen some incredible advances in smartphone processing power along with a wealth of feature improvements like faster Wi-Fi and cellular speeds and larger, higher resolution displays. However, battery technology, for the most part, hasn't kept up. There are a few major battery suppliers but Sony is currently an underdog, commanding just 8 percent of the market for compact lithium-ion batteries. Its three largest competitors — Samsung (SDI), Panasonic and LG Chem — each command around 20 percent of the market. In an effort to change that, Sony is developing a new type of battery chemistry that can boost runtimes by 40 percent compared to lithium-ion batteries of the same volume. Sony's batteries use a sulfur compound instead of lithium compounds for the positive electrodes, reportedly allowing for much great energy density. Sulfur batteries can also supposedly be made 30 percent smaller than traditional lithium-ion cells while maintaining the same run times. The company is now working to ensure that the new battery chemistry is safe enough for commercial use.
No it's not. Weight energy and volumic energy are two different things. The article does not say which is which.
It's a good thing that the summary (didn't even have to click through to the article) indicates that it's using volumetric energy density for both:
"Sony is developing a new type of battery chemistry that can boost runtimes by 40 percent compared to lithium-ion batteries of the same volume. Sony's batteries use a sulfur compound instead of lithium compounds for the positive electrodes, reportedly allowing for much great energy density. Sulfur batteries can also supposedly be made 30 percent smaller than traditional lithium-ion cells while maintaining the same run times."
Weight - and therefore energy density per unit mass - isn't mentioned or implied.
The grandparent's observation is spot on--the summary is indeed saying exactly the same thing in two different ways. If you can have the same runtime in 30% less volume, you can always get 40% more runtime with the original-sized package. To within a trivial rounding error, 140% and 70% are reciprocals; they're just saying "40% improvement in volumetric energy density".
~Idarubicin
The devil is in the details. And in particular, the cost of those details and how they chip away at the results you start with.
Disclaimer: I'm by no means a battery expert in any way, shape or form. But if you read enough about battery tech, one thing that becomes clear is that it's basically a fuzzy science due to the many factors involved. Some examples:
In the lab, you may use ultra-pure compounds to construct your battery. Such compounds can be expensive though. So for mass production you'd need to use some commercial-grade material that's less pure. The contaminants in there may not matter much. Or they may. It may depend on where that commercial-grade material is sourced. One way or the other, chances are performance / longevity / capacity is reduced vs. your lab sample.
In the lab, there's lots of things you could try with the materials used. Nano-size structures, layers a few atoms thick deposited on some base material, etc, etc. But for production, none of that matters as you have to be able to actually mass-produce it. And at low enough cost. Which means most of of those nifty tricks will be out. Possibly exactly those tricks that made the improvement.
In the lab, you'll have carefully controlled conditions. Once it's turned into a product, not so. Cells may be overcharged, over-discharged, dropped, dented, overheated, etc. Providing sufficient safety margins / features for that, can easily nullify those gains seen in the lab. A cell that sees most of its cycles around 40 degrees C may have a vastly different cycle life than one operating at 20 degrees C. Etc, etc.
Last but not least: it's a long road from lab to product. As explained above: many factors involved.
The reason why consumers "prefer" bigger phones is not because people want a change of clothing with bigger pockets... but the faster CPUs and such require more area to deal with heat.
Of course, I've been told by someone in the industry that nobody would give up CPU and RAM for a smaller phone, but it would be nice to have a phone about the size of an iPhone 4.
I work in the industry. I can tell you that the size is due to the display. It's not primarily due to heat dissipation. The manufacturers are convinced (based on trends and sales) that people want big phones with 5" or larger screens.