Separation of cathode particles and aluminum current foil in lithium-ion battery by high-voltage pulsed discharge Part II: Prospective life cycle assessment based on experimental data.

This series of papers addresses the recycling of cathode particles and aluminum (Al) foil from positive electrode sheet (PE sheet) dismantled from spent lithium-ion batteries (LIBs) by applying a high-voltage pulsed discharge. As concluded in Part I of the series (Tokoro et al., 2021), cathode particles and Al foil were separated in water based on a single pulsed power application. This separation of LIB components by pulsed discharge was examined by means of prospective life cycle assessment and is expected to have applications in LIB reuse and recycling. The indicators selected were life cycle greenhouse gas (LC-GHG) emissions and life cycle resource consumption potential (LC-RCP). We first completed supplementary experiments to collect redundant data under several scale-up circumstances, and then attempted to quantify the uncertainties from scaling up and progress made in battery technology. When the batch scale of pulsed discharge separation is sufficiently large, the recovery of cathode particles and Al foil from PE sheet by pulsed discharge can reduce both LC-GHG and LC-RCP, in contrast to conventional recycling with roasting processes. Due to technology developments in LIB cathodes, the reuse of positive electrode active materials (PEAM) does not always have lower environmental impacts than the recycling of the raw materials of PEAM in the manufacturing of new LIB cathodes. This study achieved a proof of concept for resource consumption reduction induced by cathode utilization, considering LC-GHG and LC-RCP, by applying high-voltage pulsed discharge separation.

Separation of cathode particles and aluminum current foil in Lithium-Ion battery by high-voltage pulsed discharge Part I: Experimental investigation.

To enable effective reuse and recycling processes of spent lithium-ion batteries (LiBs), here we develop a novel electrical method based on a high-voltage pulsed discharge to separate cathode particles and aluminum (Al) foil. A cathode particle sample was mechanically separated from a LiB, cut into 30-mm × 80-mm test pieces, and subjected to a high-voltage electrical pulse discharge from either end in water. At a voltage of 25 kV, 93.9% of the cathode particles separated from the Al foil. These particles were easily recovered by sieving at 2.36 mm because the Al foil retained its shape. Some Al contaminated the particles owing to generation of hot plasma and subsequent shock waves; however, the Al concentration in the recovered cathode particles was limited to 2.95%, which is low enough to allow for further cobalt and nickel recovery by hydrometallurgical processing. The results of heat balance calculations obtained from the current waveforms suggested that polyvinylidene fluoride, the main component of the adhesive in the cathode particle layers, melted and lost its adhesion through Joule heating of the Al foil at the maximum current of 19.0 kA at 25 kV. Almost 99% of the recovered cathode particles maintained their chemical composition and form after separation, and therefore could potentially be directly reused in LiBs.

Micro-gas analysis system for measurement of nitric oxide and nitrogen dioxide: respiratory treatment and environmental mobile monitoring.

In this paper, novel microsystems for gas analysis and gas generation are described. The same microchannel devices covered with a gas permeable membrane were used for both the gas collection and the gas generation. For the first time, a dual liquid flow system was utilized in a micro-gas analysis system. Even though micropumps are utilized in the dual line microsystem, a good baseline was obtained in the NO2 measurement with Griess-Saltzman chemistry. The system was developed for on-site measurements in medical treatment; the treatment is of respiratory disease syndrome by NO inhalation and the monitoring is of the product NO and the harmful byproduct NO2. The system was also applied to mobile atmospheric monitoring. Chemical NO generation using the microchannel device was investigated for safe NO inhalation as an alternative to a NO generator based on pulsed arc discharge.

Sequential multiple analyses of atmospheric nitrous acid and nitrogen oxides.

Sequential injection analysis (SIA) was applied to multi-gas monitoring for atmospheric analysis. HONO, NO(2) or NO was collected in an individual diffusion scrubber in which the channel array was filled with either HCl or triethanolamine solution. All analytes were collected in the form of nitrite ions in the scrubber, and were transferred via a 12-port selection valve into a 2.5-ml syringe. The reagent, 3-amino-1,5-naphthalenedisulfonic acid (C-acid) solution was subsequently introduced into the syringe, and inter-mixed with the nitrite sample, whereafter the mixed solution was transferred to a heated reactor and held for 3min at 100 degrees C. After that, the sample/reagent solution was returned to the syringe and alkalinized. Then, the final solution was analyzed using a homemade fluorescence detector. Atmospheric HONO, NO(2) and NO were successfully monitored 3 or 4times/h. The limits of detection were 0.22, 0.28 and 0.35ppbv for HONO, NO(2) and NO, respectively. It was demonstrated for the first time that SIA is a good tool for multi-gas atmospheric analysis. These nitrogen-oxygen compounds are interconvertible, and the simultaneous measurement of these gases is important. Especially, HONO is a source of OH radicals which contribute greatly to atmospheric pollution, and indeed atmospheric chemistry. This method allows the three gases to be measured using one system. The NO(2) and NO data obtained by SIA was compared with those obtained using chemiluminescence instrument. SIA has been successfully applied to atmospheric measurements. Interestingly, it was observed that HONO levels rose toward the end of periods of rain.