Nanofluidic Membrane with Spent Battery Residues for Efficient Energy Generation.

Harvesting energy in the ambient environment has become a dominant energy source and is promising toward a sustainable perspective. However, developing an energy generator with readily available raw materials and continuous output performance remains a challenge. Herein, we have demonstrated that a nanofluidic membrane with an asymmetric structure device (ASD) design by using available raw materials spent battery residues can achieve continuous power generation. The ASD can generate a voltage of ∼0.5 V by dropping 0.1 mL of water. Detailed experimental results reveal that ions in water play a synergistic role in enhancing output performance. By dropping 0.1 mL of seawater, the power output of ∼46.67 mW m-2 can be readily derived with voltage of ∼0.7 V. The work opens a viable way to generate electric power by environmental energy with facile structure design and easy-to-access materials. The output energy will greatly promote practical applications such as the power supply of low-power devices.

Selective leaching process for efficient and rapid recycling of spent lithium iron phosphate batteries.

With the continuous development of new energy vehicles, the number of decommissioned lithium iron phosphate (LiFePO4) batteries has been constantly increasing. Therefore, it is necessary to recover metal from spent LiFePO4 batteries due to the high potential for environmental protection and high resource value. In this study, sodium persulfate (Na2S2O8) was selected as the oxidant to regulate and control the oxidation state and proton activity of the leaching solution through its high oxidizing ability. Selective recovery of lithium from LiFePO4 batteries was achieved by oxidizing LiFePO4 to iron phosphate (FePO4) during the leaching process. This paper reports an extensive investigation of the effects of various factors, including the acid concentration, initial volume fraction of the oxidant, reaction temperature, solid-liquid ratio, and reaction time, on lithium leaching. Li+ reached a high leaching rate of 93.3% within 5 minutes even at a low concentration of sulphuric acid (H2SO4), and high-purity lithium carbonate (Li2CO3) was obtained through impurity removal and precipitation reactions. In addition, the leaching mechanism was analysed by both X-ray diffraction and X-ray photoelectron spectroscopy characterization. The results show that the obtained high lithium-ion (Li+) leaching efficiency and fast Li+ leaching time can be ascribed to the superior oxidizing properties of Na2S2O8 and the stability of the crystal structure of LiFePO4 during the oxidative leaching process. The adopted method has significant advantages in terms of safety, efficiency and environmental protection, which are conducive to the sustainable development of lithium batteries.

A Porous Hexagonal Prism Shaped C-In2-xCoxO3 Electrocatalyst to Expedite Bidirectional Polysulfide Redox in Li-S Batteries.

The shuttling behavior of soluble lithium polysulfides (LPSs) extremely restricts the practical application of lithium sulfur batteries (Li-S batteries). Herein, the hollow porous hexagonal prism shaped C-In2-xCoxO3 composite is synthesized to restrain the shuttle effect and accelerate reaction kinetics of LPSs. The novel hexagonal prism porous carbon skeleton not only provides a stable physical framework for sulfur active materials but also facilitates efficient electron transferring and lithium ion diffusion. Meanwhile, the polar In2-xCoxO3 is equipped with strong adsorption capacity for LPSs, which is confirmed by density functional theory (DFT) calculations, helping to anchor LPSs. More importantly, the doping of Co regulates the electronic structure environment of In2O3, expedites the electron transmission, and bidirectionally improves the catalytic conversion ability of LPSs and nucleation-decomposition of Li2S. Benefiting from the above advantages, the electrochemical performance of Li-S batteries has been greatly enhanced. Therefore, the C-In2-xCoxO3 cathode presents a good rate performance, which exhibits a low-capacity fading rate of 0.052% per cycle over 800 cycles at 5 C. Especially, even under a high sulfur loading of 4.8 mg cm-2, the initial specific capacity is as high as 903 mAh g-1, together with a superior capacity retention of 85.6% after 600 cycles at 0.5 C.