Can lithium and supercapacitors solve our predicament?

　　Batteries may ultimately end our reliance on fossil fuels, but they also carry potential environmental costs. Our next challenge is to find ways to make batteries—and the energy they store—equally clean.

　　The Great Green Dilemma

　　We are accelerating the transition to cleaner electricity, and there’s a lot of exciting progress happening right now. However, if we are to truly leapfrog into an all-electric future, there is a critical hurdle we must overcome: we need batteries that are genuinely clean. Although energy-storage technologies have advanced by leaps and bounds, we still have a long way to go before we can significantly reduce the environmental impact of batteries. That said, innovative companies are already taking steps to address this crucial challenge…

　　Is lithium what we’re looking for?

　　Lithium-ion batteries are currently the energy-storage solution of choice for manufacturers of electric vehicles, smartphones, tablets, and laptops. The reasons are readily apparent: they offer high charging efficiency, are easy to handle, and boast a higher energy density than alkaline batteries. Dubbed “white gold” by investors, lithium demand doubled between 2016 and 2018 as battery makers scrambled to secure this silvery-white alkali metal. Although an estimated 43 million metric tons of lithium exist on Earth, only about one-third of it is economically recoverable; of that recoverable portion, 87% is found in brine deposits, most of which are concentrated in the so-called “Lithium Triangle” of South America.

　　The production process for lithium, or more specifically for lithium carbonate, involves drilling wells in salt flats and pumping brine—saline, mineral-rich water—to the surface. This brine is then allowed to evaporate, after which the resulting salts are filtered out, enabling the extraction of lithium carbonate. Although this is a relatively straightforward process, it requires substantial amounts of water and typically takes 18 to 24 months to complete.

　　Audi is testing factory vehicles powered by lithium-ion batteries from electric vehicles. After the batteries are recycled, they can continue to be used in a sensible and sustainable manner.

　　Audi is among the companies seeking to make lithium-battery production faster and more environmentally sustainable. For instance, at the end of a battery’s life cycle, valuable materials can be recovered and reused in new products; in some cases, entire lithium batteries can even be repurposed for a second life, powering transportation and industrial vehicles. With this in mind, recycling retired batteries has become a key priority for Audi.

　　There is also room to increase the energy density of these batteries—thereby reducing their volume and the amount of lithium required—while simultaneously decreasing the use of rare metals such as cobalt and other expensive components.

　　Tsuyoshi Hoshino of the Japan Atomic Energy Agency’s Rokkasho Fusion Research Institute recently proposed another idea in the journal Desalination: a method for recovering lithium from seawater using dialysis. The system employs a specialized membrane that permits only lithium ions to pass through. Although it is not yet ready for commercial deployment, Hoshino says his osmotic technology “demonstrates excellent energy efficiency and ease of scale-up.”

　　Are graphene supercapacitors really super?

　　As lithium production continues to improve, experts are also vigorously promoting alternative technologies such as graphene-based supercapacitors. Although these devices may sound like something straight out of a science-fiction spaceship, they could help address the world’s energy challenges. Unlike conventional batteries, which store electrical energy chemically in redox reactions, supercapacitors store energy in an electrostatic field—much like static electricity accumulates on the surface of a balloon.

　　The addition of the “miraculous material” graphene has given rise to supercapacitors that are both powerful and lightweight. Although it is still early days, the graphene battery market is projected to reach US$115 million by 2022, with Chinese and Spanish companies already leveraging supercapacitors to power a wide range of products—from laptops to electric motorcycles.

　　However, there’s a major problem with all of this. Supercapacitors—even those made from graphene—cannot maintain their charge for very long. Just imagine how frustrating it is when your phone battery suddenly drops, and then picture how much worse it would be if you were stuck in a car miles away from a charging station!

　　Today, Audi’s electric accelerators are already being produced at a carbon-neutral plant in Brussels. Can we store clean electricity in equally clean batteries?

　　A battery that is both practical and environmentally friendly has long been regarded as the holy grail—but in Delft, the Netherlands, a team of innovators at AquaBells believes they have finally found it. The “blue battery” stores energy in… you guessed it—water—enabling 100% sustainable storage of all the green electricity generated in the Netherlands. So how does it work?

　　An electric current is passed through the brine, splitting it into concentrated brine and fresh water—a process known as electrodialysis—while simultaneously storing energy. During the second discharge phase, this process is reversed: the two streams of water are combined, releasing the stored energy, which is then converted back into an electric current via a specialized membrane stack.

　　This is a simple, safe technology with the potential to store large amounts of electrical energy for use when needed—for example, to ensure that a city’s power grid always has sufficient capacity to meet demand. Although the current pilot project in Delft is relatively small in scale, David Vermaas, head of the water battery initiative, has ambitious plans: he aims to deploy his “blue battery” at sites where saltwater and freshwater meet, such as the Netherlands’ extensive network of waterways. The energy potential is enormous.

　　Lithium-ion batteries currently offer the most practical solution for energy storage and will continue to be a key component in powering the next generation of electric vehicles. However, over the next decade or so, you may find yourself recharging from a grid powered by blue batteries. As technology continues to advance, these batteries are expected to provide a genuine alternative that will transform our relationship with renewable energy. Whether it’s electricity generation, energy storage, or propulsion for electric vehicles, the vision is for every stage of the energy journey to one day be 100% green.

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　　Source: Xianji.com

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