Lithium‐metal batteries are considered one of the most promising energy‐storage systems owing to their high energy density, but their practical applications have long been hindered by significant ...safety concerns and poor cycle stability. Solid‐state electrolytes (SSEs) are expected to improve not only the safety but also the energy density of Li‐metal batteries. The key challenge for solid‐state Li‐metal batteries lies in the low ionic conductivity of the SSEs and moreover the interface contact between the electrode and SSE. To achieve feasible solid‐state Li‐metal batteries, it is imperative that the ionic conductivity is improved, especially at the electrode–SSE interface. Herein, recent advances in interface engineering for solid‐state Li‐metal batteries are reported, mainly focusing on garnet‐type SSEs. Various materials to modify the cathode–garnet and Li–garnet interfaces by intermediate layers, alloys, and polymer electrolytes are analyzed. Structural innovations for SSEs including composite electrolytes and multilayer SSE frameworks are reviewed, along with advanced characterization approaches to probe the interfaces, which will provide further insights for garnet‐based solid‐state batteries. Future challenges and the great promise of garnet‐based Li‐metal batteries are discussed to close.
Lithium‐metal batteries are considered one of the most promising energy‐storage systems owing to their high energy density. The key challenges for Li‐metal batteries are the low ionic conductivity of the solid‐state electrolytes (SSEs) and the interface contact between the electrode and SSE. Recent advances in interface engineering for Li‐metal batteries are reported with a focus on garnet‐type SSEs.
A radiative cooling structural material Li, Tian; Zhai, Yao; He, Shuaiming ...
Science (American Association for the Advancement of Science),
05/2019, Letnik:
364, Številka:
6442
Journal Article
Recenzirano
Odprti dostop
Reducing human reliance on energy-inefficient cooling methods such as air conditioning would have a large impact on the global energy landscape. By a process of complete delignification and ...densification of wood, we developed a structural material with a mechanical strength of 404.3 megapascals, more than eight times that of natural wood. The cellulose nanofibers in our engineered material backscatter solar radiation and emit strongly in mid-infrared wavelengths, resulting in continuous subambient cooling during both day and night. We model the potential impact of our cooling wood and find energy savings between 20 and 60%, which is most pronounced in hot and dry climates.
Abstract
Nowadays, energy-saving building materials are important for reducing indoor energy consumption by enabling better thermal insulation, promoting effective sunlight harvesting and offering ...comfortable indoor lighting. Here, we demonstrate a novel scalable aesthetic transparent wood (called aesthetic wood hereafter) with combined aesthetic features (e.g. intact wood patterns), excellent optical properties (an average transmittance of ~ 80% and a haze of ~ 93%), good UV-blocking ability, and low thermal conductivity (0.24 W m
−1
K
−1
) based on a process of spatially selective delignification and epoxy infiltration. Moreover, the rapid fabrication process and mechanical robustness (a high longitudinal tensile strength of 91.95 MPa and toughness of 2.73 MJ m
−3
) of the aesthetic wood facilitate good scale-up capability (320 mm × 170 mm × 0.6 mm) while saving large amounts of time and energy. The aesthetic wood holds great potential in energy-efficient building applications, such as glass ceilings, rooftops, transparent decorations, and indoor panels.
The problem of loss of new qualified teachers has been a global issue which has a detrimental impact on the pool of future leadership positions and talented workforce in national labour markets. ...Despite the fact that a wide range of studies have investigated into the effects of mentoring and coaching on novice teacher retention, the leadership practices that highlight the development of teacher leadership capacities and resilience are currently insufficient. This article aims to examine the negative experiences of early career teachers (ECTs), who are in their first five years of teaching, and analyze how school leadership theories could support them by building positive working conditions. The development of ECTs’ sense of agency and resilience is emphasized in this paper through the utilization of two leadership theories: distributed leadership and caring leadership. It also clarifies recommendations for educational leaders and policymakers to enhance the quality of pre-service teacher education and induction programmes with the central premise that teacher professional development should be a career-long continuum.
With over 30% global land coverage, the forest is one of nature's most generous gifts to human beings, providing shelters and materials for all living beings. Apart from being sustainable, renewable, ...and biodegradable, wood and its derivative materials are also extremely fascinating from a materials aspect, with numerous advantages including porous and hierarchical structure, excellent mechanical performance, and versatile chemistry. Here, strategies for designing novel wood‐based materials via advanced nanotechnologies are summarized, including both the controllable bottom‐up assembly from the highly crystalline nanocellulose building block and the more efficient top‐down approaches directly from wood. Beyond material design, recent advances regarding the sustainable applications of these novel wood‐based materials are also presented, focusing on areas that are traditionally dominated by man‐made nonrenewable materials such as plastic, glass, and metals, as well as more advanced applications in the areas of energy storage, wastewater treatment and solar‐steam‐assisted desalination. With all recent progress pertaining to materials' design and sustainable applications presented, a vision for the future engineering of wood‐based materials to promote continuous and healthy progress toward true sustainability is outlined.
Wood‐based nanomaterials are attractive candidates for sustainable applications. Current progress in designing hierarchical mesostructures using wood‐based nanotechnologies, and sustainable applications in replacing plastics, glass, metals, as well as in energy storage, wastewater treatment, and solar steam generation is discussed.
For the first time, two types of highly anisotropic, highly transparent wood composites are demonstrated by taking advantage of the macro‐structures in original wood. These wood composites are highly ...transparent with a total transmittance up to 90% but exhibit dramatically different optical and mechanical properties.
Converting low-grade heat into useful electricity requires a technology that is efficient and cost effective. Here, we demonstrate a cellulosic membrane that relies on sub-nanoscale confinement of ...ions in oxidized and aligned cellulose molecular chains to enhance selective diffusion under a thermal gradient. After infiltrating electrolyte into the cellulosic membrane and applying an axial temperature gradient, the ionic conductor exhibits a thermal gradient ratio (analogous to the Seebeck coefficient in thermoelectrics) of 24 mV K
-more than twice the highest value reported until now. We attribute the enhanced thermally generated voltage to effective sodium ion insertion into the charged molecular chains of the cellulosic membrane, which consists of type II cellulose, while this process does not occur in natural wood or type I cellulose. With this material, we demonstrate a flexible and biocompatible heat-to-electricity conversion device via nanoscale engineering based on sustainable materials that can enable large-scale manufacture.
Solar steam generation is regarded as one of the most sustainable techniques for desalination and wastewater treatment. However, there has been a lack of scalable material systems with high ...efficiency under 1 Sun. A solar steam generation device is designed utilizing crossplane water transport in wood via nanoscale channels and the preferred thermal transport direction is decoupled to reduce the conductive heat loss. A high steam generation efficiency of 80% under 1 Sun and 89% under 10 Suns is achieved. Surprisingly, the crossplanes perpendicular to the mesoporous wood can provide rapid water transport via the pits and spirals. The cellulose nanofibers are circularly oriented around the pits and highly aligned along spirals to draw water across lumens. Meanwhile, the anisotropic thermal conduction of mesoporous wood is utilized, which can provide better insulation than widely used super‐thermal insulator Styrofoam (≈0.03 W m−1 K−1). The crossplane direction of wood exhibits a thermal conductivity of 0.11 W m−1 K−1. The anisotropic thermal conduction redirects the absorbed heat along the in‐plane direction while impeding the conductive heat loss to the water. The solar steam generation device is promising for cost‐effective and large‐scale application under ambient solar irradiance.
A low‐cost steam generation device is demonstrated with 80% conversion efficiency under 1 Sun. The heat transfer and fluidic transport directions are decouple, utilizing the mesostructure of wood. The anisotropic thermal conduction redirects the absorbed heat in‐plane while impeding heat loss into bulk water. Nanoscale pits and spirals in crossplanes function as efficient water supply channels.
Garnet-type solid-state electrolytes have attracted extensive attention due to their high ionic conductivity, approaching 1 mS cm
, excellent environmental stability, and wide electrochemical ...stability window, from lithium metal to ∼6 V. However, to date, there has been little success in the development of high-performance solid-state batteries using these exceptional materials, the major challenge being the high solid-solid interfacial impedance between the garnet electrolyte and electrode materials. In this work, we effectively address the large interfacial impedance between a lithium metal anode and the garnet electrolyte using ultrathin aluminium oxide (Al
O
) by atomic layer deposition. Li
La
Ca
Zr
Nb
O
(LLCZN) is the garnet composition of choice in this work due to its reduced sintering temperature and increased lithium ion conductivity. A significant decrease of interfacial impedance, from 1,710 Ω cm
to 1 Ω cm
, was observed at room temperature, effectively negating the lithium metal/garnet interfacial impedance. Experimental and computational results reveal that the oxide coating enables wetting of metallic lithium in contact with the garnet electrolyte surface and the lithiated-alumina interface allows effective lithium ion transport between the lithium metal anode and garnet electrolyte. We also demonstrate a working cell with a lithium metal anode, garnet electrolyte and a high-voltage cathode by applying the newly developed interface chemistry.
All-solid-state Li-batteries using solid-state electrolytes (SSEs) offer enhanced safety over conventional Li-ion batteries with organic liquid electrolytes due to the nonflammable nature of SSEs. ...The superior mechanical strength of SSEs can also protect against Li dendrite penetration, which enables the use of the highest specific capacity (3861 mAh/g) and lowest redox potential (−3.04 V vs standard hydrogen electrode) anode: Li metal. However, contact between the Li metal and SSEs presents a major challenge, where a large polarization occurs at the Li metal/SSE interface. Here, the chemical properties of a promising oxide-based SSE (garnet) changed from “super-lithiophobicity” to “super-lithiophilicity” through an ultrathin coating of amorphous Si deposited by plasma-enhanced chemical vapor deposition (PECVD). The wettability transition is due to the reaction between Li and Si and the in situ formation of lithiated Si. As a result, symmetric cells composed of a Si-coated garnet-structured SSE and Li metal electrodes exhibited much smaller impedance and excellent stability upon plating/stripping cycles compared to cells using bare garnet SSE. Specifically, the interfacial resistance between Li and garnet dramatically decreased from 925 to 127 Ω cm2 when lithiated Si was formed on the garnet. Our discovery of switchable lithiophobic-lithiophilic surfaces to improve the Li metal/SSE interface opens opportunities for improving many other SSEs.
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