Regulating Li-Ion Transport through Ultrathin Molecular Membrane to Enable High-Performance All-Solid-State–Battery

Solid-state lithium metal batteries with garnet-type electrolyte provide several advantages over conventional lithium-ion batteries, especially for safety and energy density. However, a few grand challenges such as the propagation of Li dendrites, poor interfacial contact between the solid electrolyte and the electrodes, and formation of lithium carbonate during ambient exposure over the solid-state electrolyte prevent the viability of such batteries. Herein, an ultrathin sub-nanometer porous carbon nanomembrane (CNM) is employed on the surface of solid-state electrolyte (SSE) that increases the adhesion of SSE with electrodes, prevents lithium carbonate formation over the surface, regulates the flow of Li-ions, and blocks any electronic leakage. The sub-nanometer scale pores in CNM allow rapid permeation of Li-ions across the electrode–electrolyte interface without the presence of any liquid medium. Additionally, CNM suppresses the propagation of Li dendrites by over sevenfold up to a current density of 0.7 mA cm⁻² and enables the cycling of all-solid-state batteries at low stack pressure of 2 MPa using LiFePO₄ cathode and Li metal anode. The CNM provides chemical stability to the solid electrolyte for over 4 weeks of ambient exposure with less than a 4% increase in surface impurities.     

Boosting Li–O2 Battery Performance via Coupling of P–N Site-Rich N,P Co-Doped Graphene-Like Carbon Nanosheets with Nano-CePO4

Development of efficient and robust cathode catalysts is critical for the commercialization of Li-O₂ batteries (LOBs). Herein, a well-designed CePO₄@N-P-CNSs cathode catalyst for LOBs via coupling P-N site-rich N, P co-doped graphene-like carbon nanosheets (N-P-CNSs) with nano-CePO₄ via a novel “in situ derivation” coupling strategy by in situ transforming the P atoms of P-C sites in N-P-CNSs to CePO₄ is reported. The CePO₄@N-P-CNSs exhibit superior bifunctional ORR/OER activity relative to commercial Pt/C-RuO₂ with an overall overpotential of 0.64 V (vs RHE). Moreover, the LOB with CePO₄@N-P-CNSs as the cathode catalyst delivers a low charge overpotential of 0.67 V (vs Li/Li⁺), high discharge capacity of 29774 mAh g⁻¹ at 100 mA g⁻¹ and long cycling stability of 415 cycles, respectively. The remarkably enhanced LOB performance is attributable to the in situ derived CePO₄ nanoparticles and the P-N sites in N-P-CNSs, which facilitate increased bifunctional ORR/OER activity, promote the rapid and effective decomposition of Li₂O₂ and inhibit the formation of Li₂CO₃. This work may provide new inspiration for designing efficient, durable, and cost-effective cathode catalysts for LOBs.     

A Carbon-Free and Free-Standing Cathode From Mixed-Phase TiO2 for Photo-Assisted Li–CO2 Battery

Li–CO₂ battery provides a new strategy to simultaneously solve the problems of energy storage and greenhouse effect. However, the severe polarization of CO₂ reduction and CO₂ evolution reaction impede the practical application. Herein, anodic TiO₂ nanotube arrays are first introduced as carbon-free and free-standing cathode for photo-assisted Li–CO₂ battery, and the photo-assisted charge and discharge mechanism is first clarified from the perspective of photocatalysis. Mixed-phase TiO₂ exhibits a long cycling life of 580 h (52 cycles) at 0.025 mA cm⁻² and delivers a high discharge specific capacity of 3001 µAh cm⁻² under UV illumination. The charge voltage dramatically reduces from 4.53 to 3.03 V under UV illumination. The improvement of photo-assisted Li–CO₂ battery performance relies on the synergistic effect of the hierarchical porous structure, strong UV absorption, efficient separation, and transfer of photo-generated electrons and holes at hetero-phase junction, and the facilitation of photo-generated electrons and holes on CO₂ reduction and CO₂ evolution reaction. This work can provide useful guidance for designing efficient photocathode for photo-assisted Li–CO₂ battery and other metal–air batteries.     

Yolk–Shell Cu2O@CuO-decorated RGO for High-Performance Lithium-Ion Battery Anode

Based on the great advantages of an inner hollow structure and excellent solid counterpart capacity, complex hierarchical structures have been widely used as electrodes for lithium-ion batteries. Herein, hierarchical yolk–shell Cu₂O@Cu O-decorated RGO(YSRs) was designed and synthesized via a multistep approach. Octahedron-like Cu₂O-decorated RGO was firstly produced, in which GO was reduced slightly while cuprous oxide was synthesized.Subsequently, the controlled oxidation ...     

Effects of Li2O3–B2O3–SiO2 addition on dielectric properties and microstructure of MgO–TiO2–ZnO–CaO ceramics

The effect of Li₂O₃–B₂O₃–SiO₂ (LBS) liquid-phase additives on the sintering, microstructures, and dielectric properties of MgO–TiO₂–ZnO–CaO (MTZC) ceramics was investigated. It was found that the sintering temperature could be lowered easily, and the dielectric properties of MTZC ceramics could be greatly improved by adding a small amount of LBS solution additives. With the addition of 10 wt% LBS, the ceramics sintered at 900 °C showed favorable dielectric properties with ε_r = 21.7, Qf = 5.0 × 10⁴ GHz, and TCF = ?21.6 ppm/ °C. The distructive physical analysis showed an excellent co-firing interfacial behavior between the MTZC ceramic and the Ag electrode. It indicated that MTZC ceramics with LBS solution additives have a number of potential applications on passive integrated devices based on the low-temperature co-fired ceramics technology.     

Effects of Li addition on the corrosion behaviour and biocompatibility of Mg(Li)–Zn–Ca metallic glasses

Magnesium alloys with suitable corrosion behaviour and good mechanical properties are desired for biodegradable materials. In the current study, novel Mg–Li-based metallic glasses (MGs) demonstrate potential clinical applications as implantable biodegradable materials. The amorphous structure of MGs provides suitable elastic modulus with human bone. The enhanced corrosion resistance of MGs realises a uniform corrosion process, as well as maintains a stable acid-based environment, and increases cell proliferation. A schematic model is proposed to illustrate the corrosion mechanisms of MGs. Adding Li significantly improves the corrosion resistance of MGs. Both the indirect cytotoxicity and direct cell culture assays are conducted using transfected osteoblasts (hFOB) cells. Results show that the novel Mg–Li–Zn–Ca MGs have good biocompatibility.     

Effects of enhanced solution treatment on microstructure and mechanical properties of Al–Cu–Li–Sc alloy

Two enhanced solution treatments (ESTs) were applied to an Al–Cu–Li–Sc alloy. Results showed that the ESTs reduced the amount and size of the soluble phases, and promoted the recrystallisation of the α–Al matrix and the precipitation of the Al₂CuLi precipitate (T₁), which improved the yield strength, tensile strength and elongation of the alloy. Although the precipitation strengthening of the T₁ phase and the strengthening resulting from grain refinement of the α–Al matrix caused by the recrystallisation contributed equally to the strength increment, the EST process led to a greater proportional increase in the strengthening resulting from grain refinement than it did in the precipitation strengthening of the alloy.     

Thermal properties of Mg–Li and Mg–Li–Al alloys

Abstract

The present work is a study of the thermal properties of Mg–xLi–y Al with x= 4, 8 and 12 wt-% and y= 0, 3 and 5 wt-% as a function of temperature in the range 20–375°C. The thermal diffusivity and coefficient of thermal expansion (CTE) have been measured and the thermal conductivity calculated. The thermal diffusivity of all alloys decreases with an increasing content of lithium. The CTE of the single phase alloys Mg–4Li and Mg–12Li has a linear character, and the CTE of Mg–12Li is higher than that of Mg–4Li. The influence of thermal stresses in the two phase alloy Mg–8Li is perceptible in terms of temperature dependence of the CTE. In Mg–4Li–3Al and Mg–4Li–5Al, an influence of the solution of AlLi phase on all the studied thermal properties has been found.     

Effects of MgO on properties of Li2O–Al2O3–SiO2 glass–ceramics for LTCC applications

Li₂O–Al₂O₃–SiO₂ (LAS) glass–ceramics for low temperature co-fired ceramics (LTCC) application were prepared by melting method, and the effects of MgO on the sinterability, microstructure, dielectric property, thermal expansion coefficient (CTE) and mechanical character of this glass–ceramics have been studied. The X-ray diffraction images represent that the main phase is β-spodumene solid solutions. And some ZrO₂ and CaMgSi₂O₆ phases in LAS glass–ceramics are detected. The LAS glass–ceramics without additive (MgO) sintered at 800° had the dielectric properties: dielectric constant (ε_r) of 5.3, dielectric loss (tanδ) of 2.97 × 10^?3 at 1 MHz, CTE value of 1.06 × 10^?6 K^?1, bulk density of 2.17 g/cm³, and flexural strength of 73 MPa. 5.5 wt% MgO-added LAS glass–ceramic achieves densification at 800° exhibited excellent properties: low dielectric constant and loss (ε_r = 7.1, tanδ = 2.02 × 10^?3 at 1 MHz), low CTE (2.89 × 10^?6 K^?1), bulk density = 2.65 g/cm³ as well as high flexural strength (145 MPa). The results indicate that the addition of MgO is helpful to improve the dielectric and mechanical properties. The formation of CaMgSi₂O₆ crystal phase with higher CTE leads to the increase of CTE value of LAS glass–ceramics due to the increasing MgO content, and the increase of CTE is favourable for matching with silicon (3.1 × 10^?6 K^?1). The prepared LAS glass–ceramics have the potential for LTCC application.     

Boosting the Activity and Stability with Dual-Metal-N Couplings for Li–O2 Battery

Electrocatalysts with high efficiency are crucial for improving the storage capacity and electrochemical stability of lithium–oxygen batteries(LOBs). In this work, through a facile hydrothermal method, cobalt–nitrogen-doped carbon nanocubes(Co–N/C), the calcination products of zeolitic imidazolate framework(ZIF–67) are encapsulated by ultrathin C–MoS₂ nanosheets to obtain Co–N/C@C–MoS₂ composites which are used as host materials for the oxygen cathode. The synergistic effec...     

Effects of microadditions of vanadium and boron on age hardening and mechanical properties of Al–Li alloy 8090

Abstract

The effects of micro additions of vanadium and boron on the age hardening, microstructure, mechanical properties, deformation, and fracture behaviour of Al–Li alloy 8090 have been investigated. The addition of 0·6% V to 8090 alloy increases the peak hardness by 13%, the yield strength by 23%, and the ductility by 85% when optimally aged (190°C for 22·5 h). The enhancement of these properties is attributed to the refinement of S′ and δ′ precipitates and the promotion of extensive cross-slip during deformation of the vanadium containing alloys. The same amount of vanadium reduces the impact toughness of 8090 by 50%, which is attributed to the presence of coarse particles of primary Al₁₁V precipitate. Increasing the cooling rate during solidification, or adding 0·1%B, restores and slightly increases the impact toughness of the vanadium containing alloy. The effect of cooling rate is related to the amount and size of Al₁₁V precipitates, which decrease with increasing cooling rate. The addition of boron appears to modify the morphology of the Al₁₁V precipitate.

MST/1584     

A Bifunctional Photo-Assisted Li–O2 Battery Based on a Hierarchical Heterostructured Cathode

Photo-assisted charging is considered an effective approach to reducing the overpotential in lithium–oxygen (Li–O₂) batteries. However, the utilization of photoenergy during the discharge process in a Li–O₂ system has been rarely reported, and the functional mechanism of such a process remains unclear. Herein, a novel bifunctional photo-assisted Li–O₂ system is established by employing a hierarchical TiO₂–Fe₂O₃ heterojunction, in which the photo-generated electrons and holes play key roles in reducing the overpotential in the discharging and charging processes, respectively. Moreover, the morphology of the discharge product (Li₂O₂) can be modified via the dense surface electrons of the cathode under illumination, resulting in promoted decomposition kinetics of Li₂O₂ during the charging progress. Accordingly, the output and input energies of the battery can be tuned by illumination, giving an ultralow overpotential of 0.19 V between the charge and discharge plateaus with excellent cyclic stability (retaining a round-trip efficiency of ≈86% after 100 cycles). The investigation of the bifunctional photo-assisted process presented here provides significant insight into the mechanism of the photo-assisted Li–O₂ battery and addresses the overpotential bottleneck in this system.     

Influences of solid solution parameters on the microstrucuture and hardness of Mg–9Li–6Al and Mg–9Li–6Al–2Y

The microstructure evolution of Mg–9Li–6Al and Mg–9Li–6Al–2Y with the variation of solid solution parameters was investigated. Results show that, in Mg–9Li–6Al, under the condition of 340 °C × 0.5 h, the MgLi₂Al phase is dissolved in the phase of β-Li, and the AlLi phase precipitates from α-Mg phase. With the holding time being prolonged to 1 h, the precipitated AlLi distributes in the whole phase of α-Mg. Under the condition of 440 °C × 0.5 h, the AlLi phase is dissolved in the matrix, and MgLi₂Al phase precipitates from β-Li. The addition of 2 wt.% Y in Mg–9Li–6Al can promote the precipitation of MgLi₂Al phase and restrain the precipitation of AlLi phase, causing the increase of hardness of the alloy.     

NiCo2O4-Based Nanosheets with Uniform 4 nm Mesopores for Excellent Zn–Air Battery Performance

Herein, a strategy is reported for the fabrication of NiCo₂O₄-based mesoporous nanosheets (PNSs) with tunable cobalt valence states and oxygen vacancies. The optimized NiCo_2.148O₄ PNSs with an average Co valence state of 2.3 and uniform 4 nm nanopores present excellent catalytic performance with an ultralow overpotential of 190 mV at a current density of 10 mA cm⁻² and long-term stability (700 h) for the oxygen evolution reaction (OER) in alkaline media. Furthermore, Zn–air batteries built using the NiCo_2.148O₄ PNSs present a high power and energy density of 83 mW cm⁻² and 910 Wh kg⁻¹, respectively. Moreover, a portable battery box with NiCo_2.148O₄ PNSs as the air cathode presents long-term stability for 120 h under low temperatures in the range of 0 to −35 °C. Density functional theory calculations reveal that the prominent electron exchange and transfer activity of the electrocatalyst is attributed to the surface lower-coordinated Co-sites in the porous region presenting a merging 3d–e_g–t_2g band, which overlaps with the Fermi level of the Zn–air battery system. This favors the adsorption of the *OH, and stabilized *O radicals are reached, toward competitively lower overpotential, demonstrating a generalized key for optimally boosting overall OER performance.     

Processing and properties of Al–Li–SiCp composites

Al–Li–SiC_p composites were fabricated by a modified version of the conventional stir casting technique. Composites containing 8, 12 and 18 vol% SiC particles (40 mm) were fabricated. Hardness, tensile and compressive strengths of the unreinforced alloy and composites were determined. Ageing kinetics and effect of ageing on properties were also investigated. Additions of SiC particles increase the hardness, 0.2% proof stress, ultimate tensile strength and elastic modulus of Al–Li–8%SiC and Al–Li–12%SiC composites. In case of the composite reinforced with 18% SiC particles, although the elastic modulus increases the 0.2% proof stress and compressive strength were only marginally higher than the unreinforced alloy and lower than those of Al–Li–8%SiC and Al–Li–12%SiC composites. Clustering of SiC particles appears to be responsible for reduced the strength of Al–Li–18%SiC composite. The fracture surface of unreinforced 8090 Al-Li alloy (8090Al) shows a dimpled structure, indicating ductile mode of failure. Fracture in composites occurs by a mixed mode, giving rise to a bimodal distribution of dimples in the fracture surface. Cleavage of SiC particles was also observed in the fracture surface of composites. Composites show higher peak hardness and lower peak ageing time compared with unreinforced 8090Al alloy. Macroand microhardness increase significantly after peak ageing. Ageing also results in considerable improvement in strength of the unreinforced 8090Al alloy and its composites. This is attributed to formation of δ^' (Al₃Li) and S^' (Al₂CuMg) precipitates during ageing. Per cent elongation, however, decreases due to age hardening. Al–Li–12%SiC, which shows marginally lower UTS and compressive strength than the Al–Li–8%SiC composite in extruded condition, exhibits higher strength than Al–Li–8%SiC in peak-aged condition.     

Effects of Zn and Y on hot-tearing susceptibility of Mg–xZn–2xY alloys

The effect of Zn and Y on hot-tearing susceptibility (HTS) of Mg–xZn–2xY (x?=?1, 1.67, 2.67) alloys is investigated. It is found that the microstructure of the alloys is mainly composed of α-Mg, long-period stacking-ordered (LPSO) phase and W-phase. Both theoretical and experimental results illustrated that HTS of the investigated alloys is in the following order: Mg–1Zn–2Y > Mg–1.67Zn–3.34Y > Mg–2.67Zn–5.34Y. For Mg–2.67Zn–5.34Y alloy, LPSO phase content reaches at the maximum and its grain size reaches at minimum of 16.4 µm, and the pinning effect of the LPSO phase on grain boundaries is considered to be an important reason for reducing HTS of the alloy.     

Corrosion and Catalytic Properties of Co–Mo–Re Electrolytic Coatings

Materials Science - We study the corrosion properties of Co–Mo–Re electrolytic alloys deposited from citrate electrolyte with pH 3.5 and 6.3. It is shown that these coatings have high...