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Li metal is the prospective candidate of next generation anode materials. However, the growth of dendritic Li during electrochemical cycling has severely hindered the practical application of rechargeable Li-metal batteries. Herein, “seaweed” graphene paper (SGP) is designed for 3D matrix of Li metal anode to address the growth of dendrites. SGP has abundantly exposed edges of graphene sheets and realizes ultrahigh density nucleation. Compared with nonuniform lithium deposition on parallelly stacked GP which has been observed by in-situ scanning electron microscopy, electrochemical deposition behavior of Li in SGP manifests as uniformly distributed granular lithium. Significant decrease of nucleation barrier can be observed during the dendrite-free deposition. With the elimination of dendritic Li growth and excellent stability of SGP host, the lithium anode based on SGP can run over 2500 cycles without short circuit and exhibits low voltage hysteresis. When matched with cathode LiCoO2, the full battery also presents stable cycling. There is no trace of lithium dendrite even after 1200 cycles which proves continuously regulating effect on lithium dendrites by SGP host. This work further develops potential application of graphene materials in the Li anode with high reversibility for stable cycling Li metal batteries.

CsPbI3 perovskite quantum dots (QDs) have great potential in optoelectronic devices due to their suitable band-gaps, but low photoluminescence quantum yields (PLQYs) and poor phase stability seriously impede their practical application. This paper reports the synthesis of Ce3+-doped CsPbI3 QDs by a hot injection method. In the presence of the dopant (Ce3+), the highest PLQY of CsPbI3 QDs reached 99%, i.e., near-unity PLQY, and the photoluminescence (PL) emission of CsPbI3 QDs could be well maintained compared to that of the undoped ones. The photoluminescence kinetics of Ce3+-doped CsPbI3 QDs was investigated by the ultrafast transient absorption technologies, which exhibited that the Ce3+ not only increased the density of excitonic states close to the high energy excitonic states (HES), but also provided more emissive channels. Moreover, the radiative recombination rates calculated by the combination of PL lifetime and PLQY further illustrated the Pb2+ vacancies were filled with Ce3+ ions so that the PL quenching of the CsPbI3 QDs could be effectively prevented. The theoretic analysis uncovered the mechanism of the high PLQY and stable PL emission of the Ce3+-doped CsPbI3 QDs.

It is well-accepted that massive cracks in Ni-rich cathode secondary particles are the determining factors for long-term performance degradation; however, the corresponding crack generation and the...

Lithium metal is expected to become one of the most high-energy density anode materials for electronic storage device. However, sharp lithium dendrites and accumulated “dead lithium” cause the consume of electrolyte and the reduction in stability for lithium metal batteries and further lead to serious safety risks in the practical application. To alleviate this problem, we firstly construct a uniform and dense amorphous Li3PO4 thin film with thickness of 10 nm via atomic layer deposition (ALD) coating lithium metal as anode. The as-prepared Li3PO4 thin film improves the cycling life of the symmetrical batteries more than double and successfully resists the shock of high current. The growth of needle-like lithium dendrites are obviously suppressed due to film's amorphous characteristics and higher modulus. The artificial SEI layer mainly homogenizes the lithium ion flux on the electrode surface to achieve the purpose of uniform Li deposition.

Nano-ordered intermetallic compounds have generated great interest in fuel cell applications. However, the synthesis of non-preciousearly transition metal intermetallic nanoparticles remains a formidable challenge owing to the extremely oxyphilic nature and very negative reduction potentials. Here, we have successfully synthesized non-precious Co3Ta intermetallic nanoparticles, with uniform size of 5 nm. Atomic structural characterizations and X-ray absorption fine structure measurements confirm the atomically ordered intermetallic structure. As electrocatalysts for the hydrazine oxidation reaction, Co3Ta nanoparticles exhibit an onset potential of −0.086 V (vs. reversible hydrogen electrode) and two times higher specific activity relative to commercial Pt/C (+0.06 V), demonstrating the top-level performance among reported electrocatalysts. The Co-Ta bridge sites are identified as the location of the most active sites thanks to density functional theory calculations. The activation energy of the hydrogen dissociation step decreases significantly upon N2H4 adsorption on the Co-Ta bridge active sites, contributing to the significantly enhanced activity., Intermetallic nanoparticles comprised of early transition metals are attractive for fuel cell applications, but are generally limited to noble metal-based systems. Here, authors report non-precious early transition metal intermetallic nanoparticles with promising electrocatalytic performance for the hydrazine oxidation reaction.

Ni-rich layered lithium transition metal oxides are promising cathode materials for the next generation high energy density lithium ion batteries. However, high Ni content leads to severe side reactions at cathode/electrolyte interface, coupled with mechanical disintegration significantly degrading the electrochemical performance and safety. Surface coating and grain boundary (GB) engineering can respectively protect surface layer and suppress cracking issue, but direct comparisons of the individual effect of the two methods at different cycling conditions has not been fully explored. Moreover, the two methods have never been coupled together previously, let alone their coupling effect. Herein, we take LiNi0·8Mn0·1Co0·1O2 as a model material and utilize atomic layer deposition coating and annealing protocol to demonstrate the individual and coupling effects of surface coating and GB engineering on cycling stability. GB engineering is found to be more effective than surface coating in enhancing cycling stability due to suppressed intergranular cracks. Promisingly, coupling GB engineering and surface coating, we can achieve superior cycle stability even upon high voltage cycling (91% retention after 200 cycles at 2.7–4.7 V), which demonstrates the importance to simultaneously alleviate surface degradation and bulk disintegration in design of advanced cathode materials.

Quick charging of Li-ion batteries is often accompanied by rapid expansion of composite battery electrodes, resulting in the appearance of transient stresses inside the electrodes’ bulk. Although p...

The design and synthesis of efficient and cost-effective electrocatalysts are vital for rechargeable zinc–air batteries (ZABs). Here, nitrogen-doped NiCo2O4 (N-doped NiCo2O4) was prepared and used ...

Advanced anode materials possessing high performance, excellent stability, and low cost are quite insufficient for sodium ion batteries (NIBs), and there is a call for huge progress to meet the pre...

With more and more applications, the mechanical strength of graphene paper (GP) has attracted significant attention in recent years. In this report, GPs were prepared by flow-induced filtration of electrochemical exfoliated graphene sheets. By adjusting the concentration of solution, we found graphene sheets fabricated in 0.1 M K2SO4 have the thinnest average thickness. And by uniaxial in-plane tensile tests operated on a self-developed in situ scanning electron microscopy (SEM) tensile stage, the corresponding GP has the best fracture strength of 192 MPa. This is due to that the thickness decrease of exfoliated graphene will increase the quantity of interlayer crosslinks, thus improving the mechanical properties of GPs. This research may open a new way to obtain high-strength GPs for applications.

Poor stability hinders the practical application of aqueous CdTe quantum dots (QDs) in optoelectronic devices. In this work, a flocculation–precipitation method is demonstrated to host aqueous CdTe QDs in gypsum to form CdTe–gypsum nanocomposites, which is simple, effective and environmental-friendly. Ascribed to gypsum acting as a tight and robust matrix protection agent, the photo-, thermal-, anti-acid and long-term stability of CdTe QDs were remarkably improved. Moreover, this approach solved the problem of incompatibility between aqueous QDs and epoxy resin, allowing for the application of aqueous QDs in white light emitting diodes (WLEDs), based on which a WLED with the red-emission nanocomposites used as a color-conversion layer was successfully fabricated. These results indicate the potential of this technique in stabilizing aqueous QDs as well as their practical application in optoelectronic devices.

Spinel Co3O4, as conversion-type transitional metal oxide, has attracted extensive interest for LIBs anode due to its high theoretical capacity. The application of transitional metal oxide including Co3O4 anode has been proved challenging due to voltage hysteresis, bad rate capability, extremely low initial Coulombic efficiency (typically 65∼70%), and volume change induced mechanical failure. Among the facing problems, the fundamental understanding of severe capacity fading at high C-rate is clearly needed to be unveiled. In this paper, we utilized in situ transmission electron microscopy (TEM) to study the electrochemical reaction process of spinel Co3O4 anode and firstly unveiled the rate-dependent morphological and structural evolution process. It has been demonstrated that the structural evolution from pristine Co3O4 phase to the formation of Co/Li2O composites during lithiation (bias = −3 V). Impressively, the Co/Li2O composites could fully delithiated into pure tightly-contacted CoO crystals (∼1.45 nm) at lower delithiated bias (+3 V); while the lithiated products partially transformed into the CoO crystals, and further suffered a severe aggregation (∼6 nm) at higher delithiated bias (+8 V). These findings advance the understanding of the mechanism of capacity fading at high current density (C-rate) in conversion-type spinel Co3O4 anode for lithium ion batteries.

The pseudocapacitive materials, like spinel NiCo2O4 (NCO), that use Faradaic reactions to store charge have been widespread paid attention for supercapacitors application. So, it is a basic fundamental guideline that the preparation of higher-performance pseudocapacitive materials depends on achieving and accelerating more Faradaic reactions in the aspect of electrodes. In this work, based on the mentioned principle, we report a facile method that could significantly promote the capacity of NiCo2O4 nanoelectrode through annealing precursor nanowires (NWs) in different volume ratios of N2 and O2 condition. The pristine NCO (VN2: VO2 = 0:1) only exhibited inferior performance with a specific capacitance of 0.88 F cm−2 (338.5 F g-1 at 2 mA cm−2) and capacitive retention of 54% from 2 to 30 mA cm−2. While, for a comparison, the highest comprehensive performance of NCO-9 (VN2:VO2 = 9:1) electrodes delivered superior specific capacitance of 3.8 F cm−2 (1461 F g-1 at 2 mA cm−2), excellent rate retention of 77% and good cycling stability. These boosted pseudocapacitive properties both in capacity and rate capability are attributed to the severe oxygen vacancy defects introduced in nitrided NCO NWs. The involving richness-enabled oxygen defects significantly enhance the electron/ions transportation, and then efficiently alter the well-known capacitive surfacial reaction into bulk pattern in the charge-discharge cycles. This dramatically increased electron/ions kinetics and electrochemical cites for Faradaic reactions. These results provide a deep insight into correlating oxygen vacancies induced structural and chemical evolution on enhanced capacitive performances of redox-active-NiCo2O4 materials.

Selenium (Se), a congener of Sulphur (S), is widely used as a cathode material for high energy-density lithium-ion batteries, named Li–Se batteries. It has been found that nanostructured Se confined in carbonaceous can lead to significantly improved rate capability and cyclic performance. However, the underlying mechanism of carbon coatings in view of surface/interface electro-chemo-mechanical effect at nanoscale remains poorly unexploited. Herein, equipped with in-situ transmission electron microscopy (TEM), we have investigated the type of lithium ions transportation, phase transformation, and coupling mechanical behavior of carbon conformably coated Se nanowire (NW) cathode reacted with Li. Intriguingly, We find a unique lithiation mechanism that the “leapfrog phase transformation” occurs at interface between carbon coating and Se NW cathode. The increasingly accumulated Li ions in leapfrog buckled region as a new platform would react with Se to form crystalline Li2Se from surface to interior. More importantly, this interfacial diffusion pathway of Li ions uniquely differs from the surface-coating directed Li transportation engineered where in Li ions initially diffuse into coatings and then react with core materials of electrodes. Furthermore, we note a threshold diameter region of Se NWs with ~ 115–120 nm, above which the uniform carbon coating (~ 8.5 nm) shows remarkable crack and even delimitation after fully lithiation form. These observations provide reliable guidelines for the design of high-performance lithium-ion batteries by interface and surface engineering.

In this report, using atomic layer deposition (ALD) technique, TiO2 layer with different thickness is conformally deposited on the surface of MoO3 nanobelts for enhanced-performance anode. Impressively, the MoO3@85-TiO2 (85 cycles coating) nanobelts anode shows its best comprehensive value: The initial Coulombic efficiency (CE) dramatically increases from 44% to 73% compared to bare MoO3 electrode; It also delivers highest initial specific capacity of 1153.7 mAh g−1 at 100 mA g−1, which is superior to the uncoated MoO3 (427.3 mAh g−1). Additionally, MoO3@85-TiO2 nanobelts show a remarkable long-life stability from initial 913.6 to 935.8 mAh g−1 after 400 charge-discharge cycles at 400 mA g−1. The advanced TEM characterizations reveal that the TiO2 layer can experience a transition from amorphous into crystalline Li2Ti2O4 with cubic structure (a = 8.375 A) during cycling, which are acted as an efficient lithium ion conductor. Furthermore, the quantified mechanical properties demonstrate a remarkable decrease in the bending elastic modulus of MoO3@85-TiO2 nanobelts compared to that of pristine MoO3. Therefore, the boosted electrochemical performance can be attributed to efficient lithium ions transportation across the moderate conductor layer and robust mechanical integrity that the large volume variation. These results advance the understanding in the coating regulated materials for enhanced-performance LIBs.

Nowadays, applying the SLM technology to produce crack-free high-performance solution strengthened superalloys or refractory metal is still a big challenge. In this work, an innovative method via in-situ chemical doping of Y2O3 was used to solve the above problem. The results show that the Y2O3 introduced by this method forms a smooth and uniform coating on the surface of Hastelloy X spherical powders. Using this powder as the precursor, cracks in the SLM manufactured Hastelloy X can be completely eliminated. More heterogeneous nucleation sites provided by doped Y2O3 significantly reduce the grain and cell size of SLMed Hastelloy X, thereby inhibiting crack initiation and propagation. Based on the microstructural optimization, the ultimate tensile strength of Y2O3-doped Hastelloy X alloy increases significantly from 982 ± 66 MPa to 1405 ± 26 MPa, along with its yield strength increasing from 820 ± 46 MPa to 1130 ± 25 MPa. Besides, its total elongation also increases from 22.7 ± 1.7% to 27.7 ± 0.5%. The increase of strength is attributed to the strengthening effect of Y2O3 nanoparticles and the refinement of cells and grains, while the increase of total elongation is attributed to the elimination of internal cracks. The strategy of introducing uniform rare earth oxide coating on the surface of metal powders by in-situ chemical method proposed in our work provides a new perspective for SLM manufacturing high-performance solution strengthened superalloys or refractory metal prone to crack.

Based on the need for whole biomass hydrogels in biomedical applications, a dual-crosslinked hydrogel based on natural product sodium alginate (SA) were prepared. Dual-crosslinked was formed by SA crosslinking with glutaraldehyde (GA) and calcium ion (Ca2+), and the introduction of carboxymethyl cellulose (CMC) into crosslinked network to obtain excellent water-induced shape memory property. The chemical and physical crosslinking net points, formed by GA and Ca2+, as the stationary phase to hold the original shape; While hydrogen bonding interactions between CMC and SA as the switcher to fix the temporary shape in air and driving the recovery in water. The shape fixing and recovery ratio can reach 90%. The dual crosslinking effect and introduction of CMC, also strengthen the mechanical properties of hydrogels and change the size of pores in hydrogels. Cell culture experiment showed that these hydrogels are good at biocompatibility and can control the cell differentiation by adjusting the size of pores in hydrogel networks. For its excellent performance, these hydrogels can be potentially applied as biological device materials in the field such as soft tissue engineering, controlled drug release and bioactuators.

CsPbBr3 perovskite quantum dots (PQDs) have drawn much attention for their high photoluminescence quantum yield and great potential in optoelectronic applications. However, they suffer from poor stability under humid condition. This paper reports CsPbBr3 PQDs incorporated in aluminum stearate (AlSt3) matrix via an improved co-precipitation approach, in which AlSt3 not only acted as hydrophobic matrix to protect CsPbBr3 PQDs from surrounding environment, but also passivated the surface of PQDs via the coordination bond of St-Cs and St-Pb, as well as bond between Al3+ and Br−. By this method, the as-synthesized CsPbBr3-AlSt3 composites exhibited excellent stability in ambient condition even directly in water for more than 60 days. With the CsPbBr3-AlSt3 composites (green emission) used as color-conversion layer, a white light-emitting diode (WLED) was fabricated with a high color rendering index (Ra) of 90 and a low color temperature (Tc) of 4929 K. These results suggest that this method pave an effective way to stabilize CsPbBr3 PQDs, which is of great importance for their further application.

Uncontrollable dendrite growth during the repeated plating/stripping of Li ions induces short cycle life and safety issues, which has severely impeded the practical application of lithium metal battery. It is acknowledged that the solid electrolyte interphase (SEI) is pivotal for Li metal anode stabilization. Here, a lithium metal anode coated with an artificial SEI film as the working electrode is applied. The TiO2 coating layer is firstly demonstrated for the lithium metal anode protection via atomic layer deposition (ALD) method. Thanks to the ultrathin TiO2 layer, dendritic growth is suppressed and the cycling lifetime is significantly improved. Additionally, the thickness of TiO2 protective layer has been further optimized. Comparing with other different thickness TiO2 layer, 5 nm TiO2 layer is found to be the optimized parameter toward capacity, cycling stability and rate capability in both symmetric battery system and full-cell system. The TiO2 layer promoted uniform deposition of Li+ and effectively inhibited the growth of lithium dendrites. Symmetric Li/50TiO2||Li/50TiO2 battery could cycle stably for more than 1600 h at 1 mA cm−2, and more than 500 h at 3 mA cm−2 and 10 mA cm−2 current density. The Li/50TiO2||NCM622 full-cell exhibited better rate performance and long-cycle performance, which capacity retention was increased by 23.3% compared to bare electrode after 100 cycles at 0.5 C charge-discharge current density. Furthermore, the inherent working mechanism of TiO2 artificial SEI film has been proposed. This work provides an effective and new alternative method for lithium metal anodes protection, which is critical for the future design of next-generation Li metal batteries under safe operation.

Molybdenum disulfide (MoS2) has received considerable interest for electrochemical energy storage and conversion. In this work, we demonstrate a material on synthesis of a unique hierarchical hollow structure by growing layered MoS2 nanosheets on assembled graphene nanotubes via a template-sacrificed approach (named as graphene@MoS2 nanotubes). As a proof of concept, the graphene@MoS2 nanotubes as the anode materials of lithium-ion batteries exhibit excellent cycling performance at 400 mA g−1 up to 120 cycles without considerable capacity loss (830 mA h g−1, with 96.5% capacity retention) and high rate behavior (502 mA h g−1 at 2000 mA g−1), which is far beyond than that of the pure MoS2 nanosheets and even graphene@MoS2 nanosheets composites. Furthermore, combined with in-situ TEM lithiation experiments, we find a novel conversion reaction mechanism of MoS2 anodes that Li ions induce structural destruction in c-direction following a dynamic layer-by-layer dissociation with Mo/Li2S composites left, rather than well-known multistep reaction in bulk phase. The first-principles computations verify that the surfacial relaxation of Li2S to form an anti-fluorite structure on higher electric conductive LixMoS2 surface is the primarily thermodynamic driving force for activating the above-mentioned reaction. These results are envisaged to be helpful for designing durable conversion-type MoS2 anodes by surface engineering, and the hierarchical tubular feature further points out a new protocol for graphene based hybrid anode for enhanced lithium-ion batteries.

Single atom catalyst, which contains isolated metal atoms singly dispersed on supports, has great potential for achieving high activity and selectivity in hetero-catalysis and electrocatalysis. However, the activity and stability of single atoms and their interaction with support still remains a mystery. Here we show a stable single atomic ruthenium catalyst anchoring on the surface of cobalt iron layered double hydroxides, which possesses a strong electronic coupling between ruthenium and layered double hydroxides. With 0.45 wt.% ruthenium loading, the catalyst exhibits outstanding activity with overpotential 198 mV at the current density of 10 mA cm−2 and a small Tafel slope of 39 mV dec−1 for oxygen evolution reaction. By using operando X-ray absorption spectroscopy, it is disclosed that the isolated single atom ruthenium was kept under the oxidation states of 4+ even at high overpotential due to synergetic electron coupling, which endow exceptional electrocatalytic activity and stability simultaneously., While water splitting offers a carbon-neutral means to store energy, water oxidation is sluggish and corrosive over earth-abundant electrocatalysts. Here, authors show single ruthenium atoms over cobalt-iron layered double hydroxides to be effective and stable oxygen evolution electrocatalysts.

In situ scanning electron microscopy (SEM) offers a good way to investigate the structural evolution during lithiation and delithiation processes. In this paper, the dynamical morphological evolution of 3D-line-structured/unstructured Si/C composite electrodes was observed by in situ SEM. The investigation revealed the microstructural origin of large charge capacity for 3D-line-structured anodes. Based on this proposed mechanism, a coarse optimization of 3D-line-structured anodes was proposed. These results shed light on the unique advantages of using an in situ SEM technique when studying realistic bulk batteries and designing 3D electrode structures.

Lignin as a renewable natural resource has been the focus of numerical interest in applications ranging from pitch to porous carbon material. Herein, a facile approach is reported to transform lignin into porous conductive carbon structures and interdigitated circuits for supercapacitor devices using femtosecond laser direct writing. Comparative studies revealed that the laser irradiation induced tetrahedral amorphous carbon while only graphitic carbon was obtained through pyrolysis. Meanwhile, the composite membrane was easily prepared to further optimize the capacities by mixing functional materials (MoS2) into the lignin/polyacrylonitrile (PAN) composite polymers. A MoS2 decorated porous carbon network material could be fabricated through focused femtosecond pulsed laser irradiation of the corresponding composite membranes. The microstructure and spectroscopic features of these laser induced hybrid carbon materials have been deeply investigated. The supercapacitor based on lignin/PAN has high areal specific capacitances of 6.7 mF cm−2 (0.9 F cm−3) at 10 mV s−1. Moreover, doped microsupercapacitors with MoS2 demonstrated enhanced areal capacitances up to 16 mF cm−2 (2.2 F cm−3) and at 10 mV s−1, respectively. The relatively high areal capacitances indicate that the proposed method is potential for innovative manufacturing energy storage devices based on natural lignin.

The blue-emitting CsPbBr3 quantum dots (QDs) have currently received widespread attention due to high photoluminescence quantum yields (PLQYs), but their instability mainly caused by self-aggregation or environmental erosion (i.e. moisture and oxygen) should be solved to gain more progress in further application. This paper presented a feasible approach to high-quality blue-emitting CsPbBr3 QDs-polymethylmethacrylate (PMMA) films, in which PMMA provided a solid framework to protect CsPbBr3 QDs by the chelation between C O and Pb2+ ions, thus resulting in the stability of CsPbBr3 QDs. The CsPbBr3 QDs-PMMA films exhibited remarkable properties including water resistance, flexibility, deep-blue emission (465 nm), and comparatively high PLQY (45%). The blue LED fabricated by the films displayed a CIE coordinate (0.14, 0.10), which was corresponding to the standard blue CIE coordinate (0.14, 0.08) according to National Television System Committee (NTSC).

Metal oxides hold the promise of high-capacity anodes for Li-ion batteries. Lithiation of binary metal oxides proceeds with two typical mechanisms: insertion and conversion. We characterize the two-step lithiation behavior of α-MoO 3 , namely, Li intercalation in the layered α-MoO 3 leads to the formation of crystalline Li 2 MoO 3 in the early stage of lithiation, and further Li insertion coverts Li x MoO 3 to metallic Mo and amorphous Li 2 O. The intercalation process is thermodynamically more favorable and is accompanied with a minor volumetric change, while the conversion reaction is kinetically slow and induces large deformation. Furthermore, instead of showing significant Li-embrittlement as seen in typical oxides, α-MoO 3 remains defects free despite the nearly 100% repetitive volumetric change during lithiation cycles. The reaction mechanism, structural evolution, and mechanical behaviors are unveiled through coordinated in-situ transmission electron microcopy experiments on α-MoO 3 nanobelts and first-principles computational studies. The results provide fundamental perspectives in the course of developing reliable high-capacity electrodes for Li-ion batteries.

For practical application of lithium–oxygen batteries, one of the challenges is the development of efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in cathode. In this work, perovskite Sr0.9Y0.1CoO3−δ nanorods are synthesized by an electrospinning method. The performance of the Li–O2 cell with Sr0.9Y0.1CoO3−δ catalysts is better than that of the cell only with Super-P. Furthermore, modification of CoO nanoparticles on the cathode can provide an obviously improved electrochemical performance with a reduced voltage gap (∼80–140 mV), which is ascribed to the superior catalytic activity of CoO nanoparticles toward OER. All of these results demonstrate that the perovskite Sr0.9Y0.1CoO3−δ is an efficient bifunctional electrocatalyst for lithium–oxygen batteries, and the incorporation of CoO nanoparticles is an effective approach for improving the cathode performance as well.

Nanosized zeolite beta with a tuneable crystal morphology and size, rich intercrystalline mesoporosity and high catalytic activity for low-density polyethylene cracking, was fast transformed from a low-seeded, low-templated dry gel by a seeding-steam-assisted conversion method with a small quantity of water; the crystallization of zeolite beta is well induced within 28 h at a TEAOH/SiO2 of 0.1 with the aid of 1% seeds.

The amount and kinetics of intercalation and extraction of electrons and ions in electrodes is critical for high-performance Li-ion batteries (LIBs), which are rather complicated involving tight interactions of both electrochemistry and mechanics. These coupled electro-chemo-mechanical behaviors could substantially influence the number and kinetics of transferred ions and electrons and ultimately affect the performance of the entire battery system. Furthermore, the emerged surface/interface coating–engineered electrodes in both cathode and anode materials can significantly regulate the performance of batteries, while the underlying mechanism should urgently be unveiled. With the capability of resolving the structure and chemistry, advanced electron microscopy is an ideal technique for directly visualizing the interplay between electrochemistry and mechanics in both neat and modified electrode materials at atomic-to-bulk scale. This review first summaries recent progress in electron microscopy regarding electro-chemo-mechanical behaviors of both anode and cathode materials, which includes techniques of in situ/ex situ (scanning) transmission electron microscopy and scanning electron microscopy. In addition, as a comparison, the electron microscopy of how surface/interface coatings regulated electrodes is further represented. Finally, the major challenges and opportunities of electron microcopy techniques are outlined for rechargeable ion batteries. An in-depth understanding of the electrochemistry-mechanics interaction in electrodes could describe the full mechanism that governs the Li-storage performance and then provide fundamental guidelines for target-oriented LIB design and optimization.

The novel hierarchical Ni-Co sulfide nanosheet-nanotubes arrays were directly grown on Ni foam, as binder-free electrodes, have been successfully synthesized following a one-step facile hydrothermal method combined with a sulfide treatment. The initial value of the area capacitance achieved 2.28 F cm&minus, 2 at a current density of 1 mA cm&minus, 2. A high areal capacitance retention of 95.2% compared to activation-induced peak value is achieved after 3000 charge-discharge cycles, which is much better than counter Ni-Co oxide electrode (1.75 F cm&minus, 2 at 1 mA cm&minus, 2, 93.2% retention compared to activation induced peak value). The outstanding and excellent super capacitive performance is ascribed to ion-exchange reaction, which induces a flexible hollow nanotube feature and show higher conductivity, compared with Ni-Co oxide NWs. Cyclic voltammetry (CV) and Electrochemical impedance spectra (EIS) results confirmed that the synthesized electrode contains the lowest resistance at high, and at lower frequency, leading to easy penetration of electrolytes and fast transportation of electrons inside the electrode. In this proposed work, a one-step hydrothermal method has been followed, and provided for the sulfide-induced, with a noticeable electrochemical performance of nickel cobaltite compounds and supplying a promising route for high-performance supercapacitor electrodes.