Darko Kapelina believes that we are on the cusp of breakthroughs in LiON (lithium-ion) battery technology. However, none of the current efforts focus on leveraging advancements as it relates to clean sailing. The majority of the focus, as is to be expected, is in the areas of obvious transportation vehicles, such as airplanes and autos. The fact that major corporations in these industries have a vested interest in accelerating the speed of advancements in the technology means that substantial investments focused on accelerating safety and improving storage capability have been made.
Currently, corporate giants such as Boeing (the airplane manufacturer) and major auto manufacturers such as Ford, GM and Nissan (Toyota and BMW are in a partnership to develop the next generation lithium battery called lithium-air), are working aggressively with their LiON battery suppliers to insure advancements in safety, longevity, capacity, as well as a reduction in size and cost.
As of January 2013, a new World Record is on the books for battery technology. Thanks to a tiny particle resembling an egg yolk, scientists have been able to dramatically increase LiON battery storage capacity. According to their paper in Nature Communications, researchers from Stanford University and the SLAC National Accelerator Laboratory, the newly discovered material is described as a “sulfur-TiO2 yolk-shell nanoarchitecture with internal void space for long-cycle lithium-sulphur batteries.” This material can be used in the cathode of LiON batteries to overcome a key obstacle that has stumped scientists for the past two decades. The result: a fivefold increase in the amount of energy that can be stored in a LiON battery!
When this breakthrough comes to market, the gasoline and diesel engine will become obsolete, and most sailboats of the future will have access to clean, regenerative power. Darko Kapelina is interested in ideas and systems relating to regenerative sailing.

Update as of April 11, 2013

9 Apr 2013 | Switzerland
Tin nanocrystals for the battery of the future

More powerful batteries could help electric cars achieve a considerably larger range and thus a breakthrough on the market. A new nanomaterial for lithium ion batteries developed in the labs of chemists at ETH Zurich and Empa could come into play here.

They provide power for electric cars, electric bicycles, smartphones and laptops; nowadays, rechargeable lithium ion batteries are the storage media of choice when it comes to supplying a large amount of energy in a small space and light weight. All over the world, scientists are currently researching a new generation of such batteries with an improved performance. Scientists headed by Maksym Kovalenko from the Laboratory of Inorganic Chemistry at ETH Zurich and Empa have now developed a nanomaterial which enables considerably more power to be stored in lithium ion batteries.

The nanomaterial is composed of tiny tin crystals, which are to be deployed at the minus pole of the batteries (anode). When charging the batteries, lithium ions are absorbed at this electrode; while discharging, they are released again. “The more lithium ions the electrodes can absorb and release – the better they can breathe, as it were – the more energy can be stored in a battery,” explains Kovalenko.

The element tin is ideal for this: every tin atom can absorb at least four lithium ions. However, the challenge is to deal with the volume change of tin electrodes: tin crystal becomes up to three times bigger if it absorbs a lot of lithium ions and shrinks again when it releases them back. The scientists thus resorted to nanotechnology: they produced the tiniest tin nanocrystals and embedded a large number of them in a porous, conductive permeable carbon matrix. Much like how a sponge can suck up water and release it again, an electrode constructed in this way can absorb lithium ions while charging and release them when discharging. If the electrode were made of a compact tin block, this would practically be impossible.

During the development of the nanomaterial, the issue of the ideal size for the nanocrystals arose, which also carries the challenge of producing uniform crystals. “The trick here was to separate the two basic steps in the formation of the crystals – the formation of as small as a crystal nucleus as possible on the one hand and its subsequent growth on the other,” explains Kovalenko. By influencing the time and temperature of the growth phase, the scientists were able to control the size of the crystals. “We are the first to produce such small tin crystals with such precision,” says the scientist.

Using uniform tin nanocrystals, carbon, and binding agents, the scientists produced different test electrodes for batteries. “This enables twice as much power to be stored compared to conventional electrodes,” says Kovalenko. The size of the nanocrystals did not affect the storage capacity during the initial charging and discharging cycle. After a few charging and discharging cycles, however, differences caused by the crystal size became apparent: batteries with ten-nanometre crystals in the electrodes were able to store considerably more energy than ones with twice the diameter. The scientists assume that the smaller crystals perform better because they can absorb and release lithium ions more effectively. “Ten-nanometre tin crystals thus seem to be just the ticket for lithium ion batteries,” says Kovalenko.

As the scientists now know the ideal size for the tin nanocrystals, they would like to turn their attention to the remaining challenges of producing optimum tin electrodes in further research projects. These include the choice of the best possible carbon matrix and binding agent for the electrodes, and the electrodes’ ideal microscopic structure. Moreover, an optimal and stable electrolyte liquid in which the lithium ions can travel back and forth between the two poles in the battery also needs to be selected. Ultimately, the production costs are also an issue, which the researchers are looking to reduce by testing which cost-effective base materials are suitable for electrode production. The aim is to prepare batteries with an increased energy storage capacity and lifespan for the market, in collaboration with a Swiss industrial partner.

Source and top image: ETH

Darko Kapelina is interested in ideas and systems relating to clean regenerative sailing.