Valorising Waste PET Bottles into Carbon Anodes for Li-ion Battery using Ionothermal Carbonisation: A Preliminary Study

Waste PET bottles (WPB) is fast becoming an environmental nuisance and its valorization to carbon anode could be a sustainable method to manage this waste and also develop cheap and highperformance carbon materials for Li-ion batteries (LIBs). Carbonaceous materials derived from WPB were prepared using an ionothermal carbonization (ITC) method in choline chloride urea-deep eutectic solvent system. The ITC-derived materials were subsequently annealed in air to obtain carbonaceous materials. The ITC-derived carbon displayed ultra-high nitrogen doping but lesser carbonization and graphitic ordering compared to the reference carbon material obtained using hydrothermal carbonization (HTC). Therefore, higher temperature annealing/pyrolysis was recommended for the ITC-derived carbon. The HTC-derived carbon was investigated as anode material in LIB with promising electrochemical performance. The LIB displayed stable reversible capacity of about 130 mAh/g at a current density of 0.1 mA/g after 20 cycles and an increasing Coulombic efficiency that reached 98% after the 50 th cycle. This work shows that a facile and sustainable synthesis method could be used to produce cheap activated carbons with potential applications in energy storage systems such as LIBs

Ionothermal synthesis of activated carbon from waste PET bottles as anode materials for lithium-ion batteries

Waste polyethylene terephthalate (PET) bottles have become a significant post-consumer plastic waste with attendant environmental problems. Hence, ionothermal synthesis has been used to prepare activated carbon (AC) anode materials from waste PET for both high performance and sustainable lithium-ion batteries (LIB). Particularly, using choline chloride deep eutectic salts (CU-DES) does not require post-synthesis washing and thereby reduces the complexity of the process and produces materials with unique low-surface area, higher levels of graphitization/ordering, and high nitrogen doping in the obtained ACs. The results show that the AC produced using CU-DES (PET-CU-A-ITP2) gave good electrochemical performance. Even though the material possesses a low surface area (∼23 m2 g−1), it displays a gravimetric capacity (GC) of ∼460 mA h g−1 and a coulombic efficiency (CE) of ∼53% in the 1st cycle and very good cycling performance with a capacity retention of 98% from the 2nd to the 100th cycle. The superior electrochemical performance of the PET-CU-A-ITP2 anode was found to be due to its better graphitization/ordering and dense structure which results in higher capacity, formation of less solid electrolyte interphase, and higher CE. These results show that dense carbons can be exploited as high-performance anodes in LIBs. Also, this research presents both a pathway for waste PET management and a waste-energy approach that could offer cheaper and greener LIBs to meet the sustainable development goals

A study of natural radioactivity in some building materials in Nigeria

Building materials of different brands were assessed for the concentrations of 226Ra, 232Th and 40K using HPGe detector. The activity concentrations in the measured samples ranged from 27 ± 8 to 82 ± 8 Bq kg−1 for 226Ra, 41 ± 4 to 101 ± 8 Bq kg−1 for 232Th and 140 ± 8 to 940 ± 19 Bq kg−1 for 40K, respectively. The Radium equivalent (Raeq) activity from the samples was found to be <370 Bq kg−1 as the recommended value for construction materials. This study will set a baseline data for significant standards on radiation exposure of the measured radionuclides in the selected building materials used in Nigeria

Meeting sustainable development goals via robotics and autonomous systems

Robotics and autonomous systems are reshaping the world, changing healthcare, food production and biodiversity management. While they will play a fundamental role in delivering the UN Sustainable Development Goals, associated opportunities and threats are yet to be considered systematically. We report on a horizon scan evaluating robotics and autonomous systems impact on all Sustainable Development Goals, involving 102 experts from around the world. Robotics and autonomous systems are likely to transform how the Sustainable Development Goals are achieved, through replacing and supporting human activities, fostering innovation, enhancing remote access and improving monitoring. Emerging threats relate to reinforcing inequalities, exacerbating environmental change, diverting resources from tried-and-tested solutions and reducing freedom and privacy through inadequate governance. Although predicting future impacts of robotics and autonomous systems on the Sustainable Development Goals is difficult, thoroughly examining technological developments early is essential to prevent unintended detrimental consequences. Additionally, robotics and autonomous systems should be considered explicitly when developing future iterations of the Sustainable Development Goals to avoid reversing progress or exacerbating inequalities

Meeting sustainable development goals via robotics and autonomous systems

Robotics and autonomous systems are reshaping the world, changing healthcare, food production and biodiversity management. While they will play a fundamental role in delivering the UN Sustainable Development Goals, associated opportunities and threats are yet to be considered systematically. We report on a horizon scan evaluating robotics and autonomous systems impact on all Sustainable Development Goals, involving 102 experts from around the world. Robotics and autonomous systems are likely to transform how the Sustainable Development Goals are achieved, through replacing and supporting human activities, fostering innovation, enhancing remote access and improving monitoring. Emerging threats relate to reinforcing inequalities, exacerbating environmental change, diverting resources from tried-and-tested solutions and reducing freedom and privacy through inadequate governance. Although predicting future impacts of robotics and autonomous systems on the Sustainable Development Goals is difficult, thoroughly examining technological developments early is essential to prevent unintended detrimental consequences. Additionally, robotics and autonomous systems should be considered explicitly when developing future iterations of the Sustainable Development Goals to avoid reversing progress or exacerbating inequalities

Optimizing the electrochemical performance of Li2_2MnO3_3 cathode materials for Li-ion battery using solution combustion synthesis: Higher temperature and longer syntheses improves performance

Li$_2$MnO$_3$ is the parent compound and a component of the well-studied Li-rich Mn-based layered materials (xLi$_2$MnO$_3$·(1−x)LiMO$_2$) for high capacity Li-ion batteries. Different combinations of citric acid fuel and metal nitrates (C/N) were used to optimize the electrochemical performance of Li$_2$MnO$_3$ nanoparticles by the solution combustion synthesis. Thermodynamic modelling and thermogravimmetric analysis show that the variations of C/N molar ratio affected the combustion process and the Li$_2$MnO$_3$ powder characteristics such as morphology and crystallinity. The fuel-rich composition (C/N = 0.555) with the highest adiabatic flame temperature produced Li2MnO3 cathode materials with the best electrochemical performance. The influence of sintering temperature on the crystallinity of the Li$_2$MnO$_3$ sample was investigated with high-temperature synchrotron XRD. The Li$_2$MnO$_3$ synthesized at a lower temperature (400 °C) had a better initial discharge capacity than the one synthesized at a much higher temperature (800 °C) however, it showed far poorer cycling stability. These differences in their electrochemical performance were explained on the basis of their microstructure and morphology. Furthermore, increasing annealing time at 800 °C (from 2 to 20 h) achieved phase pure materials and improved the electrochemical performance of Li$_2$MnO$_3$ powders. This improvement was due to the well defined, developed and larger particles of the samples annealed at longer times. The results show that apart from increasing synthesis temperature, varying annealing times at optimum temperature could be used to improve the functional performance of ceramic oxides

Solution Combustion-Mechanochemical Syntheses of Composites and Core-Shell xLi2MnO3⋅(1–x)LiNi0.5Mn0.3Co0.2O2xLi_2MnO_3·(1 – x )LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2 (0 ≤ x ≤ 0.7) Cathode Materials for Lithium-Ion Batteries

A combination of the solution combustion and mechanochemical syntheses (SC-MS) presents a facile, low-energy, and cost-effective method to prepare layered lithium-rich oxide (LLO) composites and core-shell structures compared to the conventional methods of preparing these compounds. The composite and core-shell structures of xLi$_2$MnO$_3$·(1 – x)LiNi$_{0.5}$Mn$_{0.3}$Co$_{0.2}$O$_2$ (0 ≤ x ≤ 0.7) were prepared using optimized SC-MS and were comparatively characterized with respect to their morphology, chemical composition, and structural and electrochemical properties. Notably, the composite cathode materials show lower discharge capacities compared to the core-shell cathode materials with same target stoichiometry but comparable cycling stability, which was ascribed to their probably higher contents of Ni$^{3+}$. Apart from giving larger unit cell volumes, the core-shell cathode materials with a Ni-rich core and a Mn-rich shell gave a combination of higher discharge capacity, good cyclability, lower irreversible capacity loss, better rate performance, and thermal stability. This confirms the efficiency of the core-shell strategy in improving the electrochemical performance of LLOs, especially for systems with a Ni-rich component. These results show that the SC-MS method could be used for the large-scale synthesis of electrode materials for high power Li-ion batteries