Electricity as we know it has a major flaw—it is surprisingly hard to store. To date, one of our best solutions is lithium-ion batteries, an advancement that was recently recognized with the 2019 Nobel Prize in Chemistry.* During the past few decades, these devices have enabled the miniaturization of energy-storage devices, currently used in laptop computers, mobile phones, and electric vehicles. Despite their high energy density, lithium-ion batteries still present some downsides. In fact, if you were to use state-of-the-art batteries to power your house, you would need a device of over one ton to store enough energy for one week. Moreover, the scarcity of lithium and cobalt limits future developments and their links to conflict minerals clash with SDG 12 on sustainable production patterns. Hence, new devices such as dual-ion batteries (DIBs) have attracted the attention of the scientific community. While in classic lithium-ion batteries, only cations move along the electrolyte, in DIBs both anions and cations participate in the energy storage mechanism. They also exhibit some fundamental differences in the cell setup—in DIBs the ions in the electrolyte are also active, which directly influences characteristics such as capacity and voltage.
DIBs could be an interesting alternative to grid storage applications. Their electrodes can be manufactured out of cheap and abundant materials using greener routes. Traditionally, the fabrication of lithium-ion batteries involves the use of toxic organic solvents. On the other hand, researchers envisioned fabricating DIBs using water processing, enhancing sustainability and reducing the cost. Although the first DIB prototypes also relied on lithium, now chemists have found new solutions that use sodium, potassium, or aluminium—all of which are copious and widely available worldwide. Discovered only a few years back, DIBs are still facing some challenges – researchers need to better understand their mechanism in order to improve their capacity, reversibility, and lifetime. Yet, industrial innovations are starting to blossom. Recently, a team in China reported the first prototypes for viable pouch cells based on the dual-ion approach and companies such as Ricoh and Power Japan Plus are already investing in this attractive technology. The latter has even tempted electric car maker Tesla with “a fully recyclable battery that charges faster than lithium while still allowing a range of 300 miles.” In brief, DIBs present a series of advantages in terms of cost, lifetime, and sustainability that align with SDG 7. Besides, they provide a safer choice, according to experts. Since there is no intrinsic oxygen available in the cell, the ‘fire tetrahedron’ is incomplete, preventing accidental combustion.
References:
Gomollón-Bel, F. Chem. Int. 2019, 41 (2), 12-17.
By Jaideep Khandekar
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