Electrochemical synthesis of nanowire anodes from spent lithium ion batteries

A Short Review on Various Engineering Applications of Electrospun One-Dimensional Metal Oxides

The growing scientific interest in one-dimensional (1D) nanostructures based on metal-oxide semiconductors (MOS) resulted in the analysis of their structure, properties and fabrication methods being the subject of many research projects and publications all over the world, including in Poland. The application of the method of electrospinning with subsequent calcination for the production of these materials is currently very popular, which results from its simplicity and the possibility to control the properties of the obtained materials. The growing trend of industrial application of electrospun 1D MOS and the progress in modern technologies of nanomaterials properties investigations indicate the necessity to maintain the high level of research and development activities related to the structure and properties analysis of low-dimensional nanomaterials. Therefore, this review perfectly fits both the global trends and is a summary of many years of research work in the field of electrospinning carried out in many research units, especially in the Department of Engineering Materials and Biomaterials of the Faculty of Mechanical Engineering and Technology of Silesian University of Technology, as well as an announcement of further activities in this field.

Recycling of electrode materials from spent lithium-ion power batteries via thermal and mechanical treatments

This study developed a physical separation process that recovers active cathode materials from current collectors in spent lithium-ion power batteries (LIBs). The physical separation process, implemented via thermal and mechanical treatments, was examined based on cohesive zone models (CZMs) and verified by physical separation experiments. The most efficient condition was determined by optimising the key parameters (temperature and time) of selective heating. Among several mechanical separation methods, high-speed shearing best separates positive electrode materials into active cathode materials (LiFePO₄) and current collectors (Al fragments). The separation effect was verified by computing the dissociation rate and microscopic observation of the separated materials. The feasibility and efficiency of the above process were assessed in a work-of-force analysis, flow field simulation, high-speed crushing experiment and material property analysis. The above analyses realised a feasible, efficient and environmentally friendly separation route without changing the chemical structure and properties of the electrode materials. Under non-high (energy-conserving) temperature conditions, the LiFePO₄ dissociation rate stabilises at 80-85%. Under high-speed crushing, the LiFePO₄ dissociation rate reaches 85% at 32,000-r/min crushing and a maximum shearing velocity of the blade edge v ≈ 500 m/s. This approach can effectively recycle electrode materials, gain valuable resources and can be used to recycle and utilise spent LIBs, thus addressing two grave issues - environmental pollution and resource wastage to achieve the sustainable development of LIBs and electric vehicle industry.

Precipitation and Crystallization Used in the Production of Metal Salts for Li-Ion Battery Materials: A Review

Li-ion battery materials have been widely studied over the past decades. The metal salts that serve as starting materials for cathode and production, including Li2CO3, NiSO4, CoSO4 and MnSO4, are mainly produced using hydrometallurgical processes. In hydrometallurgy, aqueous precipitation and crystallization are important unit operations. Precipitation is mainly used in the processes of impurity removal, separation and preliminary production, while controlled crystallization can be very important to produce a pure product that separates well from the liquid solution. Precipitation and crystallization are often considered in the development of sustainable technologies, and there is still room for applying novel techniques. This review focuses on precipitation and crystallization applied to the production of metal salts for Li-ion battery materials. A number of novel and promising precipitation and crystallization methods, including eutectic freeze crystallization, antisolvent crystallization, and homogeneous precipitation are discussed. Finally, the application of precipitation and crystallization techniques in hydrometallurgical recycling processes for Li-ion batteries are reviewed.

Growth of Less than 20 nm SnO Nanowires Using an Anodic Aluminum Oxide Template for Gas Sensing

Stannous oxide (SnO) nanowires were synthesized by a template and catalyst-free thermal oxidation process. After annealing a Sn nanowires-embedded anodic aluminum oxide (AAO) template in air, we obtained a large amount of SnO nanowires. SnO nanowires were first prepared by electrochemical deposition and an oxidization method based on an AAO template. The preparation of SnO nanowires used aluminum sheet (purity 99.999%) and then a two-step anodization procedure to obtain a raw alumina mold. Finally, transparent alumina molds (AAO template) were obtained by reaming, soaking with phosphoric acid for 20 min, and a stripping process. We got a pore size of < 20 nm on the transparent alumina mold. In order to meet electroplating needs, we produced a platinum film on the bottom surface of the AAO template by using a sputtering method as the electrode of electroplating deposition. The structure was characterized by X-ray diffraction (XRD). High resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) with X-ray energy dispersive spectrometer (EDS) were used to observe the morphology. The EDS spectrum showed that components of the materials were Sn and O. FE-SEM results showed the synthesized SnO nanowires have an approximate length of ~10–20 μm with a highly aspect ratio of > 500. SnO nanowires with a Sn/O atomic ratio of ~1:1 were observed from EDS. The crystal structure of SnO nanowires showed that all the peaks within the spectrum lead to SnO with a tetragonal structure. This study may lead to the use of the 1D structure nanowires into electronic nanodevices and/or sensors, thus leading to nano-based functional structures.