Comparative life cycle assessment of LFP and NCM batteries including the secondary use and different recycling technologies.

Lithium iron phosphate (LFP) batteries and lithium nickel cobalt manganese oxide (NCM) batteries are the most widely used power lithium-ion batteries (LIBs) in electric vehicles (EVs) currently. The future trend is to reuse LIBs retired from EVs for other applications, such as energy storage systems (ESS). However, the environmental performance of LIBs during the entire life cycle, from the cradle to the grave, has not been extensively discussed. In this study, life cycle assessment (LCA) was used to quantify and compare the environmental impacts of LFP and NCM batteries. Apart from the phases of production, the first use in EVs, and recycling, the repurposing of retired LIBs and their secondary use in the ESS were also included in the system boundary. Also, the environmental impacts of various recycling processes were evaluated. The LCA results suggested that the NCM battery had better comprehensive environmental performance than the LFP one but shorter service life over the whole life cycle. In China, the first and secondary use phases contributed most to the environmental impacts with electricity mostly generated from fossil fuels. The LIB production phase was relevant to all assessed impact categories and contributed more than 50% to Abiotic Depletion Potential (ADP elements) particularly. The environmental loads could be mitigated through the recovery of metals and other materials. And, hydrometallurgy was recommended for recycling waste LIBs by better environmental advantages than pyrometallurgy and direct physical recycling. Sensitivity analysis revealed that by optimizing the charge-discharge efficiency of LIBs, particularly LFP batteries, all environmental burdens could be considerably decreased. Therefore, improving the electrochemical performance of LIBs and increasing the use proportion of clean energy were crucial to reduce the environmental impacts over their entire life cycle.

Unveiling the recycling characteristics and trends of spent lithium-ion battery: a scientometric study.

The recycling of spent lithium-ion batteries (LIBs) is both essential to sustainable resource utilization and environmental conservation. While spent batteries possess a resource value, they pose an environmental hazard at the same time. Since the start of development to recycle spent LIBs in 1990s, important contributions have been made and a number of achievements have been accomplished by scholars globally. Therefore, it is valuable to summarize the developments on spent LIB recycling and to analyze the characteristics and trends comprehensively. A review of the progress in this field will provide guidance for future development. In this study, recycling characteristics and developing trends including the research foundation, milestone, research hotspot, key technologies, and emerging trends were identified based on visual scientometric analysis followed by a discussion on future research directions in this area. For the analysis, 1041 publications in English were collected, summarized, and categorized. The distribution of scientific publications on spent LIB recycling from 1995 to 2020 displayed an increasing trend in numbers. China made the biggest contribution with 528 publications and basically cooperated with all other countries. The research fields with the highest contributions were "engineering", "chemistry", and "environmental science and technology". The keywords recovery, lithium ion battery, and cobalt appeared in high frequency. "Metal value" was identified as the most frequently used keyword which began to burst in 2005 and ended in 2013.

Degradation of tetracycline in a schorl/H2O2 system: Proposed mechanism and intermediates.

Schorl could perform as an extremely promising catalyst for decomposing tetracycline hydrochloride (TC) due to its high degradation efficiency, low cost, chemical stability, easy recovery and repeatable utilization. Comparisons of TC degradation indifferent systems showed that schorl/H2O2 system exhibited the optimum pollutant elimination and TOC removal efficiencies. Kinetics and possible mechanisms of TC degradation were clarified. The OH generated on the schorl surface and O2-/HO2 were the main reactive species responsible for TC oxidation. Six possible intermediates were identified, and possible transform mechanisms and pathways were explored. Active radicals were inclined to attack the CC double bond, dimethylamino and phenolic moieties of TC molecular. The principal intermediate products were generated through N-demethylation, oxidation and rearrangement.