In 2017, UC Riverside turned waste glass bottles into lithium-battery anode material; one bottle could supply 3-5 pouch cells, while coin cells kept 1,420 mAh/g after 400 cycles

Most people empty the last drink from a glass bottle and toss it in the recycling bin, never thinking about it again. In 2017, a team of engineers at UC Riverside took one such bottle and turned it into battery material. UC Riverside's official research announcement explains that the team at UC Riverside's Bourns College of Engineering turned waste glass into anode material for lithium-ion batteries. The article says one bottle can create either hundreds of coin cells or three to five pouch cells. The batteries made from the glass bottle had a capacity of 1,420 mAh/g after 400 charge cycles, a figure reported in the underlying Scientific Reports study. For readers conscious of phone use and waste, those numbers are worth unpacking.

A landfill problem hiding in plain sight

Part of the reason this research matters comes down to sheer volume. According to the United States Environmental Protection Agency, the United States produced 12.3 million tons of glass in 2018, 7.6 million tons of which were dumped into landfills in the same year, comprising 5.2 percent on average of all landfill inputs across the country. Glass does not biodegrade. It can persist for a very long time, so UC Riverside set out to find a new use for it.

Turning bottle glass into battery-grade silicon

The process is simple enough for a basic chemistry lesson. Prof. Cengiz Ozkan and Prof. Mihri Ozkan ground discarded bottles into powder and used a chemical reaction to transform the silicon dioxide in the glass into nano-silicon. They then coated the nano-silicon with carbon to stabilize it, creating what they call a carbon-coated, glass-derived silicon anode. The research team has noted that silicon anodes can store up to 10 times more energy than the graphite anodes used in commercial batteries, making silicon a promising alternative anode material. The main problem is expansion and contraction during charge cycles, but reducing particle size to the nanoscale has helped with other materials.

Decoding 1,420 mAh/g after 400 cycles

Battery specifications can often be unfamiliar, so here is a simpler explanation. After 400 charge/discharge cycles, the material retained a capacity of 1,420 mAh/g. This means the coin-sized battery retained much of its performance after 400 charge/discharge cycles. The study also found that the laboratory cells exceeded commercially available coin cells in both gravimetric capacity and cycle stability.

One bottle, hundreds of batteries

The key detail is this: Changling Li, a graduate student in materials science and engineering at UC Riverside who led the work, said that silicon extracted from one typical bottle could be used to make hundreds of small coin-shaped batteries or a few large pouch cells, the rectangular, flexible batteries used in phones and laptops. Either way, it is a large amount of useful material that would otherwise have gone to landfill.

The payoff for EVs and everyday electronics

If you read reviews of electric vehicles or regularly check when your phone battery hits 10 percent, this research may interest you. A new anode material can increase the driving range of electric cars and the time between charges of electronic devices. Because the material comes from broken glass in landfills, it may appeal to younger consumers who care about the companies they support and their environmental impact.

The honest caveat: This is still lab-stage work

What has not happened yet is important to note. The results are from coin cell and early pouch cell testing at a university. This isn't a battery that has been tested in a car or phone and is ready for market. There's a long path from initial research to commercialization of any battery technology. The university's technology transfer office has filed a patent application for the process, which suggests commercial potential, but a patent filing is not the same as commercialization.

The road ahead for a recycled bottle

Waste glass will continue to accumulate, and the need for better batteries will remain. Research like this suggests one possible way to address both issues at once using readily available materials. Whether or not this method reaches the market, it suggests that a bottle in your recycling bin may be worth more than you expect.