Synergetic pyrolysis of LiNi1/3Co1/3Mn1/3O2 and PET plastics shed light on highly efficient and energy saving strategies for battery recovery and regeneration

With the increasing consumption of lithium-ion batteries (LIBs), it is highly desirable to develop efficient and energy saving strategies for battery material recovery and regeneration. In this study, a synergetic pyrolysis strategy was developed to recover valuable metals by thermal treatment of LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with the addition of polyethylene terephthalate (PET) plastics. It is the first time that PET plastics served as reaction additives to accelerate the lattice decay and thermal decomposition of NCM materials. With the assistance of PET synergetic pyrolysis, NCM started to decompose at only 400°C, and was completely converted to Li2CO3, MnO and Ni-Co alloy after thermal reaction at 550°C for 30 min with the NCM:PET mass ratio of 1.0:0.3. The thermal degradation of PET was retarded with various free radicals and reductive gases released. Furthermore, a density functional theory (DFT) calculation verified the combination preference of O-Li bonding between horizontal PET and the Li terminated NCM (001) surface. The surface adsorption caused atom capture and the free radical/gaseous reduction reactions explained the synergetic effect of PET on promoting the lattice destruction of NCM cathode materials. Moreover, the complete decomposition of NCM well benefited the post treatment, and the subsequent 2 separation of Li and transition metals (TM: Ni, Co and Mn) could be efficiently achieved by water washing method. Regenerated NCM was also synthesized by using the recovered Li- and TM- containing products as feedstocks. As a result, this study provided a novel NCM recovery strategy with significant privileges of chemical free, energy saving, highly efficient and scalable. Meanwhile, this strategy proposed an ideal solution for the minimization and utilization of PET plastics. In addition, the mechanism study provided a theoretical guidance on the industrialization and broaden application of PET plastic for effective metal recovery from spent LIBs by this synergetic pyrolysis strategy

Waste to treasure: Regeneration of porous Co-based catalysts from spent LiCoO2 cathode materials for efficient oxygen evolution reaction

The increasing demand for portable electronic devices and electric vehicles (EV) has triggered the rapid growth of rechargeable Li-ion batteries (LIBs) markets. However, in the near future, it is predicated a large amount of spent LIBs will be scrapped, imposing huge pressure on environmental protection and resources reclaiming. The effective recycling or regeneration of the spent LIBs not only relieves the environmental burdens but also avoids the waste of valuable metal resources. Herein, a porous Co9S8/Co3O4 heterostructure is successfully synthesized from the spent LiCoO2 (LCO) cathode materials via a conventional hydrometallurgy and sulfidation process. The fabricated Co9S8/Co3O4 catalyst proves high catalytic activity towards oxygen evolution reaction (OER) in alkaline solution, with an overpotential of 274 mV to achieve the current density of 10 mA cm-2 and a Tafel slope of 48.7 mV dec-1. This work demonstrates a facile regeneration process of Co-based electrocatalysts from the spent LiCoO2 cathode materials for efficient oxygen evolution reaction

Efficient recovery of lithium as Li2CO3 and cobalt as Co3O4 from spent lithium-ion batteries after leaching with p-toluene sulfonic acid

Rechargeable lithium-ion batteries (LIBs) have been widely used in consumer electronics and electric vehicles. In terms of environmental restrictions and circular economy, proper treatment of spent LIBs is of great significance for achieving sustainable development. In this study, organic p-toluene sulfonic acid (PTSA) was employed to recycle valuable Li and Co elements from the spent LIBs for production of battery raw materials (e.g. Li2CO3 and Co3O4). Operation parameters such as PTSA concentration, hydrogen peroxide (H2O2) concentration, solid-toliquid ratio, leaching temperature and leaching time, were systematically investigated. Under the optimal conditions (0.9 vol% H2O2, 1.5 mol L 1 PTSA, 30 g L 1 solid-to-liquid ratio, 80 ◦C, and 60 min), the leaching efficiencies of commercial LiCoO2 could reach ~100% and 99% for Li and Co, respectively, while the corresponding values were about 95% and 93% for the spent LiCoO2. In addition, the selective precipitation of Co-rich compounds in cooled leachate allowed an effective separation of Co from the mixture. The high recovery yield of Co3O4 and Li2CO3 demonstrated the great potential of the PTSA-assisted leaching strategy in hydrometallurgical recycling of the spent LIBs for practical applications. Overall, this proposed recovery process is simple, efficient, and environmentally friendly and is of vital importance for rational treatment of spent LIBs

V2V Routing in VANET Based on Heuristic Q-Learning

Designing efficient routing algorithms in vehicular ad hoc networks (VANETs) plays an important role in the emerging intelligent transportation systems. In this paper, a routing algorithm based on the improved Q-learning is proposed for vehicle-to-vehicle (V2V) communications in VANETs. Firstly, a link maintenance time model is established, and the maintenance time is taken as an important parameter in the design of routing algorithm to ensure the reliability of each hop link. Aiming at the low efficiency and slow convergence of Q-learning, heuristic function and evaluation function are introduced to accelerate the update of Q-value of current optimal action, reduce unnecessary exploration, accelerate the convergence speed of Q-learning process and improve learning efficiency. The learning task is dispersed in each vehicle node in the new routing algorithm and it maintains the reliable routing path by periodically exchanging beacon information with surrounding nodes, guides the node’s forwarding action by combining the delay information between nodes to improve the efficiency of data forwarding. The performance of the algorithm is evaluated by NS2 simulator. The results show that the algorithm has a good effect on the package delivery rate and end-to-end delay

Exonuclease III protection assay with FRET probe for detecting DNA-binding proteins

We describe a new method for the assay of sequence-specific DNA-binding proteins in this paper. In this method, the sensitive fluorescence resonance energy transfer (FRET) technology is combined with the common DNA footprinting assay in order to develop a simple, rapid and high-throughput approach for quantitatively detecting the sequence-specific DNA-binding proteins. We named this method as exonuclease III (ExoIII) protection assay with FRET probe. The FRET probe used in this assay was a duplex DNA which was designed to contain one FRET pair in the center and two flanking protein-binding sites. During protein detection, if a target protein exists, it will bind to the two protein-binding sites of the FRET probe and thus protect the FRET pair from ExoIII digestion, resulting in high FRET. However, if the target protein does not exist, the FRET pair on the naked FRET probe will be degraded by ExoIII, resulting in low FRET. Three kinds of recombinant transcription factors including NF-κB, SP1 and p50, and the target protein of NF-κB in HeLa cell nuclear extracts, were successfully detected by the assay. This assay can be extensively used in biomedical research targeted at DNA-binding proteins

A Novel Multiobjective Optimization Method Based on Sensitivity Analysis

For multiobjective optimization problems, different optimization variables have different influences on objectives, which implies that attention should be paid to the variables according to their sensitivity. However, previous optimization studies have not considered the variables sensitivity or conducted sensitivity analysis independent of optimization. In this paper, an integrated algorithm is proposed, which combines the optimization method SPEA (Strength Pareto Evolutionary Algorithm) with the sensitivity analysis method SRCC (Spearman Rank Correlation Coefficient). In the proposed algorithm, the optimization variables are worked as samples of sensitivity analysis, and the consequent sensitivity result is used to guide the optimization process by changing the evolutionary parameters. Three cases including a mathematical problem, an airship envelope optimization, and a truss topology optimization are used to demonstrate the computational efficiency of the integrated algorithm. The results showed that this algorithm is able to simultaneously achieve parameter sensitivity and a well-distributed Pareto optimal set, without increasing the computational time greatly in comparison with the SPEA method