Spray‐Dried Mesoporous Mixed Cu‐Ni Oxide@Graphene Nanocomposite Microspheres for High Power and Durable Li‐Ion Battery Anodes

Exfoliated graphene‐wrapped mesoporous Cu‐Ni oxide (CNO) nanocast composites are developed using a straightforward nanostructure engineering strategy. The synergistic effect of hierarchical mesoporous CNO nanobuilding blocks that are homogeneously wrapped by graphene nanosheets (GNSs) using a rapid spray drying technique effectively preserves the electroactive species against the volume changes resulting from the charge/discharge process. Owing to the intriguing structural/morphological features arising from the caging effect of exfoliated graphene sheets, these 3D/2D CNO@GNS nanocomposite microspheres are promising as high‐performance Li‐ion battery anode materials. They exhibit unprecedented electrochemical behavior, such as high reversible specific capacity (initial discharge capacities exceeding 1700 mAh g−1 at low 0.1 mA g−1, stable 850 and 730 mAh g−1 at 1 and 5 mA g−1 after 800 and 1300 cycles, respectively, and higher than 400 mAh g−1 at very high current density of 10 mA g−1 after more than 2000 cycles), excellent coulombic efficiency and long‐term stability (more than 3000 cycles with >55% capacity retention) at high current density that are remarkable compared to most transition metal oxides and nanocomposites prepared by conventional techniques. This simple, yet innovative, material design is inspiring to develop advanced conversion materials for Li‐ion batteries or other energy storage devices

Exercising the condominium tenure option: a case study of the Canadian housing market

With data from the National Survey of Condominium Occupants conducted by Canada Mortgage and Housing Corporation, the relevant differences between a sample of renters who decided to purchase a condominium and a sample of homeowners who decided to sell their dwelling to buy a condominium are described. The subpopulation differed with respect not only to life-cycle stages and household economic resources but also to stated housing preferences and future housing plans. For example, previous renters were found to be younger households in the earlier stages of the life cycle who purchased lower priced condominiums with more borrowed funds than previous homeowners. A proportion of previous renters, however, were found to be entering the condominium sector late in life. Previous owners, the majority of whom moved from the freehold ownership market, preferred condominium ownership as means of gaining greater physical security and less direct maintenance responsibilities and, therefore, searched for only condominium housing. On the other hand, tenants sought initially to gain entrance into the freehold ownership market before deciding on the purchase of condominiums. Previous tenants are planning to use the equity of their condominiums to move into single detached houses within a short period of time, whereas for previous owners the condominium sector presents a final stage in housing demand. It is concluded that life-cycle stages and household economic resources continue to dominate a household's tenure transition, but this must also be combined with tenure and housing preferences as well as long-term or future housing plans.

Recent Developments on All Solid Na-ion Polymer Batteries for Large-scale Energy Storage

The life style of modern civilization is strongly dependent on the use of portable devices, which necessarily require safe and very efficient storage and conversion energy systems. Nowadays, lithium-ion batteries (LiBs) represent the most widely used technology in this respect. One of the arduous challenges in this field is the substitution of conventional liquid electrolytes based on organic solvents, which are volatile and hazardous. Solid polymer electrolytes (SPEs) exhibit appealing properties to replace liquid electrolytes. Moreover, research efforts are directed towards alternative systems to LIBs, because lithium is expensive and its resources are geographically constrained. Sodium exhibits suitable electrochemical properties, close to those of lithium, and it is very abundant. These features make Na-based batteries proficient candidates to replace LiBs, particularly when large-scale energy storage is envisaged. Here, we offer an overview of our recent developments on polymer electrolytes for Na-ion batteries. Polymer electrolytes were prepared through different techniques, exploiting both UV-curing and simple casting. All samples were thoroughly characterized in the physico-chemical and electrochemical viewpoint. They exhibited excellent ionic conductivity and wide electrochemical stability window, which ensure safe operation at ambient conditions. Electrochemical performances in lab-scale devices are presented, evaluated by means of cycling voltammetry and galvanostatic charge/discharge cycling exploiting different electrode materials (prepared by water-based procedures with green carboxymethylcellulose as binder). Work on Na-ion polymer batteries for moderate temperature application is at an early stage, only lab-scale cells were demonstrated so far. Nevertheless, with the appropriate choice and optimisation of electrode/electrolyte materials (and succesfull combination thereof), the intriguing characteristics of the newly developed SPEs here presented postulates the possibility of their effective implementation in safe, durable and high energy density secondary Na-based polymer devices conceived for green-grid storage and operating at ambient and/or sub-ambient temperatures

Novel Cellulose-based Composite Polymer Electrolytes for Green, Efficient and Durable Energy Conversion and Storage Devices

Standard dye-sensitized solar cells (DSSCs) use liquid electrolytes leading to relevant technological drawbacks: poor long-term stability, difficulty in robust and hermetic sealing, electrolyte evaporation/leakage. To improve DSSCs perspectives, recent studies are addressed to the preparation of quasi-solid electrolytes, based on polymer networks able to effectively retain redox mediator/additives. In this work, innovative biocomposite polymer electrolytes for DSSCs, both gelled and/or quasi-solid, based on mixture of polyethylene oxide (PEO) and carboxymethyl cellulose (CMC) or nanoscale microfibrillated cellulose fibres (NFCs) and containing an indigenously made liquid electrolyte containing ionic liquid, supporting salts and the I3-/I- redox couple are prepared. This is the first ever report where the useful aspects of CMC and NFCs as bio-derived DSSC electrolyte components are unravelled and required parameters are thoroughly investigated. Moreover, the performances of lab scale quasi-solid devices are presented, evaluated by means of an innovative combined photovoltaic-chemometric approach. We also present the durability of the devices inherited by different PEO vs. CMC or NFC ratios, as well as the cell response upon various wavelengths and irradiation intensities. The intriguing photovoltaic-chemometric approach allows developing devices with efficiencies in the range of 5 – 7.5 % under 1 sun irradiation (7-9 % under 0.4 sun), demonstrating outstanding durability (efficiency retention of 98% after 250 h of extreme aging conditions)

Na-Ion Polymer Batteries: Cheap and Easily Processable Electrolytes for Large-scale Energy Storage

The life style of modern civilization is strongly dependent on the use of portable devices, which necessarily require safe and very efficient storage and conversion energy systems. Nowadays, lithium-ion batteries (LiBs) represent the most widely used technology in this respect. One of the arduous challenges in this field is the substitution of conventional liquid electrolytes based on organic solvents, which are volatile and hazardous. Solid polymer electrolytes (SPEs) exhibit appealing properties to replace liquid electrolytes. Moreover, research efforts are directed towards alternative systems to LIBs, because lithium is expensive and its resources are geographically constrained. Sodium exhibits suitable electrochemical properties, close to those of lithium, and it is very abundant. These features make Na-based batteries proficient candidates to replace LiBs, particularly when large-scale energy storage is envisaged. Here, we offer an overview of our recent developments on polymer electrolytes for Na-ion batteries. Polymer electrolytes were prepared through different techniques, exploiting both UV-curing and simple casting. All samples were thoroughly characterized in the physico-chemical and electrochemical viewpoint. They exhibited excellent ionic conductivity and wide electrochemical stability window, which ensure safe operation at ambient conditions. Electrochemical performances in lab-scale devices are presented, evaluated by means of cycling voltammetry and galvanostatic charge/discharge cycling exploiting different electrode materials (prepared by water-based procedures with green carboxymethylcellulose as binder). Work on Na-ion polymer batteries for moderate temperature application is at an early stage, only lab-scale cells were demonstrated so far. Nevertheless, with the appropriate choice and optimisation of electrode/electrolyte materials (and succesfull combination thereof), the intriguing characteristics of the newly developed SPEs here presented postulates the possibility of their effective implementation in safe, durable and high energy density secondary Na-based polymer devices conceived for green-grid storage and operating at ambient and/or sub-ambient temperatures

Cellulose Nanofibres for the Next-Generation of Eco-Friendly Energy Storage Devices

In order to lower the cost and reduce the environmental impact of Li-ion batteries (LiBs), efforts must be devoted to reduce the amount of inactive components in the cell, to substitute synthetic polymer binders / separators and organic solvents with low-cost and biosourced materials and to develop new eco-friendly processes for the manufacture of cell components. Natural nanoscale-microfibrillated cellulose (NMFC) fibers are readily available; they show stiffness, impressive mechanical robustness, low weight and, furthermore, their preparation process is easy and does not involve chemical reactions. They can significantly reinforce polymer electrolytes already at low filler loadings and also replace the commonly used PVdF as binder for self-standing and flexible electrodes, thus serving as a promising candidate for bio-composite production. Here we review the use of paper-making technique for manufacturing low cost bio-inspired all-paper Li-ion polymer cells, constituted by NMFC-binded paper-electrodes, and NMFC reinforced polymer electrolytes. The use of NMFC as filler/binder leads to produce high performing, safe and extremely flexible electrolytes for LiBs. No organic solvents or synthetic polymer binders are used during the entire electrode/electrolyte/cell preparation process. Materials and procedures are also extended to other “beyond-LiB” technologies, such as Na-ion and Li-S, thus demonstrating the possibility of obtaining “truly green” energy storage devices in the near future. Noteworthy, the all-paper-cell can be easily re-dispersed in water by simple mechanical stirring, as common paper handsheets and battery materials can be recovered using well-known water-based recycling process

Polymer Electrolytes for Green, Safe and Robust All-Solid Na-ion Batteries

The modern life style that we are enjoying depends on energy storage systems in which the role of Li-ion batteries (LiBs) is peerless. However, state-of-the-art LiBs are approaching the verge of possible technological imagination, particularly in terms of energy density. Some researchers argue that next-gen secondary batteries should switch to heavier elements such as sodium. Indeed, when it comes to gigantic energy storage systems for the electricity grid and/or other non-portable applications where size does not matter, Na-based systems can be an effective and intelligent choice. Nevertheless, research on NiBs’ components is at the very beginning, particularly for what concerns the electrolyte, where standard organic liquid electrolytes are mainly used. Unfortunately, their flammable nature jeopardizes the safety of these large scale systems, which in case of failure may lead to thermal runaways. In this work, an overview is provided on quasi-solid polymer electrolytes specifically conceived and developed for Na-ion secondary cells, based on polyethylene oxide (PEO), acrylates/methacrylates and/or mixtures thereof. Eventually, pyranose ring based natural additives and/or low volatile plasticizers are added along with supporting sodium salts to improve specifically defined characteristics. All the sample are thoroughly characterized in the physic-chemical and electrochemical viewpoint. The performances in lab scale devices are presented, evaluated by means of cycling voltammetry and galvanostatic charge/discharge cycling exploiting different electrode materials (prepred by water-based procedures exploiting carboxymethylcellulose as binder). We also present preliminary aging resistance tests of the devices inherited by different solid electrolytes, as well as the cell response upon various temperatures and current regimes. So far, work on Na-ion polymer batteries for moderate temperature application is at an early stage, only lab-scale small battery cells are demonstrated. Nevertheless, with the appropriate choice and development of electrode/electrolyte materials, the overall characteristics of the SPEs here developed postulates the possibility of their effective implementation in safe, durable and high energy density secondary Na-based polymer devices conceived for green-grid storage and operating at ambient and/or sub-ambient temperatures