We would all love less expensive batteries that are safe, reliable, and possibly even better performing than what we have now. What if recycling our throw-aways gave us “new” batteries with refined materials that improve their performance?
A current paper from the Royal Society for Chemistry may hold a key to producing such cheaper, better batteries. The complete entry expands on the idea of reclaiming materials in used batteries in an efficient, cost-effective way. The findings come to light with good timing, considering recent concerns over lithium mining and availability.
Conflicted over Conflicts
Battery materials are selected for factors such as their inherent ability to shuttle ions between a cathode and anode, the positive and negative poles of a battery. Electrodes may contain lithium, cobalt, and nickel, among other elements.
Cobalt, for instance, is a so-called “conflict mineral,” sourced from places like the Democratic Republic of the Congo using child labor. Such minerals are often mined using “artisanal and small-scale mining (ASM),” often accompanied by “high levels of corruption” and “ethnic conflict.” The Council on Foreign Relations explains that easy answers are not in the offing, unfortunately. So many families rely on the meager income from such mining that the biggest exporters, including China, are working “formalizing” the extraction of such minerals and devising programs to mitigate the many evils involved.
In the abstract for the Royal Society paper, members of two Chinese academic groups point out, “With the growing applications of lithium-ion batteries (LIBs) in many areas, their recycling becomes a necessary task. Although great effort has been made in LIB recycling, there remains an urgent need for green and energy-efficient approaches.”
Since the materials being recycled would preclude their extraction under unfortunate circumstances, there would be social and economic consequences for producing countries, making the necessary choices even harder. The responsible necessity for such recycling, however, would mean much less planet-warming energy use, as with aluminum. GreenBiz.com reports the average beer or pop can “contains an average of 73 percent recycled content.” This saves an estimated 90 percent in extraction and refining costs.
Trying to balance the economic and social harm done to an extracting region and its people against the environmental harm of such extraction makes this an almost untenable problem.
Two Schools in China
Two Beijing groups combined resources on the cathode recycling project:
- Beijing Engineering Research Center of Process Pollution Control, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences
- School of Chemical Engineering, University of Chinese Academy of Sciences
Researchers were attempting to answer whether they could devise, “A greener, simpler and more energy-efficient strategy to recycle and regenerate faded LiCoO2 (lithium cobalt oxide) cathode materials with high electrochemical performance.” Researchers claim a simple, non-destructive approach that is environmentally friendly.
Forging a circular path for the materials in lithium ion batteries (LIBs) is essential to the economic development of these cells. Researchers note that LIBs in consumer products such as cell phones and portable computers last only one to three years, while transportation batteries can serve for eight or more years. Waste, especially in consumer electronics, often ends up in landfills rather than being reused or even upcycled.
The paper highlights the dangers of landfill dumping. “By 2020, the number of spent LIBs in China’s CEs products will reach about 5.5 billion. If handled improperly, toxic and flammable fluorine-containing organic electrolytes and heavy metals such as nickel, cobalt and copper will ooze out of these LIBs. According to the report, 4,000 tons of spent LIBs contain more than 1,100 tons of heavy metals and 200 tons of toxic electrolytes. If spent LIBs are disposed of in landfill, it may cause toxic heavy metals to penetrate into the groundwater, causing serious environmental pollution. Likewise, if these LIBs are burned as general solid waste, a considerable amount of toxic gas will be generated, thereby polluting the atmosphere.”
On a more hopeful note, the researchers see these dumped LIBs as potential “urban mines,” with ready-to-recycle materials that can be made possibly better than new. This needs to take place locally, rather than transporting these materials to countries where lax standards enable child labor for the recycling, for instance. Years ago, your editor researched “junk” cathode ray tubes from TVs and computers that were shipped to Southeast Asian countries, where virtually no environmental or child labor laws offered protections governing their being melted down in open-air smelters. The long-term effects are horrifying.
Transporting used batteries adds to the environmental burden by shipping tons of material back and forth between the Far East and points of use in Europe and the Americas. As seen recently, such materials may end up stuck in a canal or waiting delivery offshore, another waste.
Mitigating the Hazards
Having pointed out the various hazards posed in the pre-treatment of LIB materials, including air, ground and water pollution, the paper’s authors offer some hope. To mitigate those hazards, the paper discusses the idea of “green chemistry” and other environmentally conscious methods of extracting the electrolyte and other reusable materials from the LIBs. The active materials in the cells can be reconstituted into “black mass,” a base for making new batteries.
One technique, “aqueous exfoliating and extracting solution (AEES)” used “sodium salt as the main raw material… for the separation of electrode materials. By optimizing the solvent concentration, the recovery efficiencies of the electrolyte, aluminum foil, copper foil and electrode materials reached 95.6%, 99.0%, 100% and nearly 100%, respectively.”
Another technique, “direct regeneration” involves, “direct lithium supplement of spent cathode materials by physical and chemical methods, [which] restore their electrochemical performance.”
Overall, the researchers looked at several techniques and stages in recycling, including the current state of the art. Regardless of impurities that may be introduced in the process and the need for stringent controls, the economic and environmental benefits of recycling are too huge to ignore.
The researchers look at the phases in recycling batteries. This includes a number of pretreatments, direct regeneration, ultrasonic enhancement, hydrometallurgy, pyrometallurgy, biological metallurgy, and other processes that show the many difficulties involved. Nonetheless, they hold out the promise of recycling’s benefits at all stages. The paper is long, but well worth at least skimming to gain an appreciation of how to make batteries while protecting the world on many fronts.