Researchers at Washington State University are in the process of developing tin anodes, which could create a more efficient, longer-lasting lithium-ion battery.
According to market research firm International Data Corporation, smartphone shipments surged 55 percent in the fourth quarter of 2011, to 158 million units from 102 million a year ago. By the end of the year, one in three cellphones shipped worldwide was a smartphone, the agency said.
As smartphone prices continue to drop, more consumers are upgrading so they can take advantage of the wide range of features these devices offer, from accessing the internet to using downloadable software applications, or apps, that range from games to GPS programs.
The mobile device boom is fueling lithium-ion battery demand
As smartphone use rises and the devices themselves grow more complex, demand for the lithium-ion batteries that power them has soared. (Lithium-ion batteries are also used in a range of other technologies, from hybrid and electric cars to laptops).
According to a 2011 report from technology research firm IHS iSuppli, the lithium-ion battery market is expected to expand 80 fold between 2012 and 2020, at which point it will be worth $5.8 billion a year.
Unfortunately, as anyone who owns a modern computer or smartphone knows, the batteries themselves have not kept up with the demands that new devices are making of them, forcing users to recharge frequently. That’s a major drag on further technological development. It’s also one of the factors keeping electric vehicles from matching gasoline engines in performance and range.
Tin could boost lithium-ion battery capacity – and lower costs
The Washington State team, led by Grant Norton, a professor at the university’s School of Mechanical and Materials Engineering, recently filed patents on a new process that involves making the battery’s anode out of tin nanowires (or “whiskers”) instead of graphite, which is what the anodes are made of today.
Here’s how it works. Currently, lithium-ion batteries contain two electrodes: an anode and a cathode. When you charge the batteries, the lithium ions move from the cathode to the anode, where they are stored. When the battery is being used, the flow reverses and the ions move to the cathode, creating an electrical current.
Tin whiskers naturally form on tin surfaces over time, and have been a problem for tin’s use in electronic devices because they can cause short circuits. The Washington State team originally set out to control the growth of these whiskers before deciding to put what they had learned toward extending lithium-ion battery life.
“It’s caused many, many millions of dollars in failures of microelectronic devices over many, many decades,” Norton told the Seattle Post-Intelligencer. “The earliest example that I found in the literature was radar problems back in the Second World War that were caused by tin whisker growth on the tin-plated electronics.”
Norton and his team believe their innovation could triple the capacity of lithium-ion batteries.
The researchers have manually grown tin whiskers up to 10 millimetres long for the purpose. Their process involves growing the whiskers directly onto copper foil using a common process called electroplating, which skips another step in making batteries – mixing graphite with a bonding material – making the new anodes cheaper than those in use today.
Another plus: tin-anode batteries will look exactly the same as current models, so device-makers won’t have to change their designs to accommodate them.
What it means for the tin market
Switching to tin anodes could have a big impact on demand for the metal. The most obvious benefit is that it would introduce a new and fast-growing market for tin. Right now, the majority of the world’s tin production is used to make solder and tin plating, as well as alloys, particularly bronze. About half of all tin production is used to make solder.
Secondly, tin could help lithium-ion batteries replace other types of batteries in different uses.
For example, right now, most gas-powered cars use lead-acid batteries, mainly because they are cheaper to produce than today’s lithium-ion batteries and have higher capacity. Tin anodes could help lithium-ion batteries close the gap and come into use in the automotive market, which is expected to grow quickly as car demand rises in emerging markets.
Norton and his team are currently building and testing batteries using the new anodes. If all goes well, they aim to bring their invention to market within a year.
Securities Disclosure: I, Chad Fraser, hold no positions in any of the companies mentioned in this article.