No abstract

It is very important to recycle the waste biomass resources for the environment protection and the circular economy. For this purpose, the waste old loofah was carbonized at 800°C for 1 h in the inert nitrogen gas (N2) atmosphere for lithium ion battery anode. The resultant waste-loofah-derived carbon was investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, nitrogen adsorption and desorption, galvanostatic charge/discharge, cyclic voltammetry and alternating current impedance. The results suggested that the waste-loofah-derived carbon powders consisted of many concomitant microparticles and nanoparticles with a specific surface area of about 492 m2/g. Furthermore, the waste-loofah-derived carbon anode also delivered high electrochemical lithium (Li) storage activity. For example, the initial specific discharge capacity was about 697 mAh/g, and the reversible discharge capacity was about 187 mAh/g at 1000 mA/g for 500 cycles and still about 98 mAh/g even at 3000 mA/g for 500 cycles, exhibiting good cycling stability. High surface area and structural defects may jointly contribute to high electrochemical performances.

As one kind of metal–organic framework material, zinc l-phenylalanine chelate may combine the merits of organic and inorganic components at the molecular level, thus making it a preferred anode active material. However, reports about zinc l-phenylalanine chelate anodes for lithium (Li) ion batteries are still scarce at the moment. Herein, shape-controlled synthesis of zinc l-phenylalanine chelate was carried out through a facile liquid-phase precipitation reaction and subsequent lyophilization. The obtained zinc l-phenylalanine chelate was investigated by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, galvanostatic charge/discharge and cyclic voltammetry. The results suggest that zinc l-phenylalanine chelate appeared as uniform nanofibers about 140 nm diameter and 2–5 μm long. Furthermore, the zinc l-phenylalanine chelate nanofiber anode exhibited satisfactory electrochemical performances. For example, the initial specific discharge capacity was as high as 255 mAh/g at 100 mA/g and the reversible capacity remained 109 mAh/g even at 1000 mA/g for 200 cycles. Additionally, the possible lithium-storage mechanism was also explored. The synergistic effect of the combination of organic/inorganic components at the molecular level, regular nanofiber-like morphology and structural cavities may facilitate good strain accommodation, short ionic/electronic transport paths and high electrochemical performance.

Expired medicines in the environment may cause the pollution and resource waste if they are not reasonably recycled. Therefore, it is very instructive to exploit the non-medical values of expired medicines. Herein, such an attempt to recycle expired aminophylline was made as the anode active material of lithium ion batteries (LIBs) for the first time. The microstructure and chemical element component of the expired aminophylline were confirmed by using the methods of scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Furthermore, the feasibility of using an expired-aminophylline-based anode in LIBs was evaluated by galvanostatic charge/discharge and cyclic voltammetry. To be satisfactory, the reversible specific discharge capacities of expired-aminophylline-based anode were maintained at 268·8 mAh/g at 50 mA/g for 200 cycles and 140 mAh/g even at 500 mA/g for 1000 cycles. In addition, after coupling with a commercial lithium cobalt (III) oxide (LiCoO2) cathode, the resultant full cell also delivered 130 mAh/g at the 100th cycle at 100 mA/g. These satisfactory results may not only pave a way for the reasonable exploitation of the non-medical values of expired medicines but also offer good inspiration and strategy to develop sustainable energy and circular economy.

The wide application and oversupply of various medicines are inevitably accompanied by the production of massive amounts of expired medicines, which can trigger the environmental contamination and waste of resources if these are not reasonably managed. For this reason, the efforts were made to recycle two expired medicines (lithium carbonate (Li2CO3) and ferrous sulfate (FeSO4) tablets) simultaneously into magnesium ion-doped lithium iron phosphate (LiFePO4; LFP)/carbon (C) powders through a facile high-temperature solid-state reaction. In addition, the economic feasibility was analyzed and discussed. The results suggested that 0·51 wt% magnesium ions were successfully doped into the lithium (Li) site of LFP/carbon, and the corresponding molecular formula was Li0·92Mg0·04FePO4/C, which resulted in the double effects: a decrease in the unit cell volume and an increase in the electronic conductivity. Furthermore, the magnesium ion/LFP/carbon cathode also exhibited better electrochemical lithium-storage performance compared with the undoped LFP/carbon cathode, indicating high application feasibility in lithium-ion batteries. Additionally, the recycling process was economically profitable, which would stimulate the development of the circular economy of waste expired medicines and lithium-ion batteries.