Energy Storage Materials as Emerging Nano-contaminants

Abstract

New and emerging nanotechnologies are increasingly using nanomaterials that undergo significant chemical reactions upon exposure to environmental conditions. The rapid advent of lithium ion batteries for energy storage in mobile electronics and electric vehicles is leading to rapid increases in the manufacture of complex transition metal oxides that incorporate elements such as Co and Ni that have the potential for significant adverse biological impact. This Perspective summarizes some of the important technological drivers behind complex oxide materials and highlights some of the chemical transformations that need to be understood in order to assess the overall environmental impact associated with energy storage technologies.

Energy Starvation in Daphnia magna from Exposure to a Lithium Cobalt Oxide Nanomaterial

“…In the case of LCO, its band gap energy is similar to that of CO 3 O 4 nanoparticles shown to negatively impact metabolism in Zhang et al (2.7 versus 2.53 eV respectively), ,, supporting the possibility that LCO’s band gap may explain its metabolic impacts in this and other studies. , Zhang et al also show oxidation of cytochrome c by these metal oxide ENMs, but ultimately attribute impacts to general oxidative stress . Hamers proposes that the toxicity of LCO may be due to the reduction of Co 3+ to Co 2+ during metal release into the aqueous solution, with concomitant oxidation of other species to produce ROS . LCO has been shown to oxidize the nonspecific ROS-sensitive fluorescent dye CM-H 2 DCFDA in trout gill cells and oxidize the Fe–S center of aconitase in C.…”

“…The mechanism by which LCO and other metal oxide ENMs may be able to impact metabolism has been suggested in the literature, but only from the standpoint of ROS generation and oxidative stress, ultimately missing what may be a far more nuanced process with broad implications: the ability of metal oxide ENMs to participate in redox chemistry. , Zhang et al demonstrate that the overlap of the conduction band of metal oxide ENMs with the biological redox potential is predictive of toxicity, including reduced NADH dehydrogenase activity and ATP production . In the case of LCO, its band gap energy is similar to that of CO 3 O 4 nanoparticles shown to negatively impact metabolism in Zhang et al (2.7 versus 2.53 eV respectively), ,, supporting the possibility that LCO’s band gap may explain its metabolic impacts in this and other studies. , Zhang et al also show oxidation of cytochrome c by these metal oxide ENMs, but ultimately attribute impacts to general oxidative stress .…”

“…One class of transition-metal-oxide ENM that is relatively understudied in the nanotoxicology literature are lithium intercalating cathode materials used in lithium ion batteries (LIBs): lithium cobalt oxide (LCO) and the alternative lithium nickel manganese cobalt oxide. The use of LIBs in electronic devices and increasingly in electric vehicles means an estimated 200 000 tons of these cathode materials were produced in 2020, and this is anticipated to rise to 380 000 tons annually by 2025, comparable to or exceeding production quantities of better-studied ENMs such as Ag and TiO 2 . − Less than 5% of these materials are currently recycled, with disposed material accumulating in landfills, where it may pose an environmental concern, ,, as some 16% of LIB cathode waste is leached from disposed material . The 60 000 tons or more of LIB leachate annually that this represents puts it on par with TiO 2 , a mass of material that could be of environmental concern. , …”

“…25 The 60 000 tons or more of LIB leachate annually that this represents puts it on par with TiO 2 , a mass of material that could be of environmental concern. 20,27 We have previously demonstrated that LCO is capable of negatively impacting survival and reproduction of the model aquatic invertebrate Daphnia magna at concentrations as low as 0.25 mg/L over 21 days. 28 D. magna is a well-established and sensitive model for aquatic toxicology specifically but with application as an important screening model for the toxicity of materials and compounds across species.…”

Expression Patterns of Energy-Related Genes in Single Cells Uncover Key Isoforms and Enzymes That Gain Priority Under Nanoparticle-Induced Stress

“… 3 In addition, current efforts are in place to decrease the size of cathode materials to improve battery performance through faster ion and electron transport and increased mechanical stability. 4 , 5 With little infrastructure in place and low economic incentive to recycle Li-ion batteries, 6 these nanomaterials are likely to end up in landfills, leachate, or as air emissions, 7 , 8 thus highlighting the need to understand the environmental and health implications of Li-ion battery materials, especially LCO NPs.…”