Advances in performance degradation mechanism and safety assessment of LiFePO4for energy storage.

In the context of "energy shortage", developing a novel energy-based power system is essential for advancing the current power system towards low-carbon solutions. As the usage duration of lithium-ion batteries for energy storage increases, the nonlinear changes in their aging process pose challenges to accurately assess their performance. This paper focuses on the study LiFeO4(LFP), used for energy storage, and explores their performance degradation mechanisms. Furthermore, it introduces common battery models and data structures & algorithms, which used for predicting the correlation between electrode materials and physical parameters, applying to SOH assessment and thermal warning. This paper also discusses the establishment of digital management system. Compared to conventional battery networks, dynamically reconfigurable battery networks can realize real-time monitoring of lithium-ion batteries, and reduce the probability of fault occurrence to an acceptably low level.

Effects of multiple firings on the translucency, crystalline phase, and mechanical strength of highly translucent zirconia.

This study aimed to clarify the effects of multiple firings on the translucency, crystal structure, and mechanical strength of highly translucent zirconia. Four types of highly translucent zirconia (LAVA Esthetic, LAVA Plus, KATANA Zirconia STML, and KATANA Zirconia HTML) were fired three times at three different temperatures, and the translucency, crystal structure, and flexural strength were evaluated before and after firing. The translucency was statistically compared using repeated-measures analysis of variance; the zirconia phase composition was assessed using X-ray diffraction followed by Rietveld analysis; and the biaxial flexural strength was assessed using Weibull analysis. The translucency of LAVA Esthetic and KATANA Zirconia HTML decreased significantly after firing, and the crystal composition of LAVA Plus and KATANA Zirconia HTML changed after multiple firings, whereas multiple firings did not affect the biaxial flexural strength of any samples. Thus, multiple firings may affect the optical properties of highly translucent zirconia.

Fracture strength of porcelain veneer on surface-treated zirconia.

In this study, we investigated the effects of surface treatment on the fracture strength of porcelain-veneered zirconia. Highly translucent 4 mol% yttria-stabilized zirconia disks (KATANA HT, Kuraray Noritake Dental) were divided into three surface-treatment groups: 1)as-sintered, 2) alumina sandblasted, and 3) ground. Crystallographic and surface-roughness analyses were conducted for each group. Veneering ceramics (Cerabien ZR, Kuraray Noritake Dental) were applied to the zirconia surfaces. The fracture strengths of the porcelain-veneered zirconia disks were measured using biaxial flexural-strength tests. Crystallographic analysis revealed that grinding and sandblasting increased the fractions of the monoclinic and rhombohedral zirconia phases. The ground specimens had a higher surface roughness than the sandblasted specimens. Weibull analysis showed no significant differences in biaxial flexural strength among the three groups. The results suggest that these surface treatments do not affect the fracture strength of porcelain-veneered zirconia.

Does speed-sintering affect the optical and mechanical properties of yttria-stabilized zirconia? A systematic review and meta-analysis of in-vitro studies.

Zirconia restorations are increasingly popular in dental treatment. Yttria-stabilized zirconia (YSZ) needs to be sintered for clinical applications and novel speed-sintering protocols are being developed for chairside treatments. Whether the properties of speed-sintered YSZ meet clinical requirements, however, remains unclear. Therefore, we conducted a systematic review and meta-analysis on the influence of speed-sintering on the optical and mechanical properties of dental YSZ according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. A literature search was conducted using PubMed, Embase, and Web of Science databases for relevant articles published between January 1, 2010 and February 28, 2022 in English, Chinese, or Japanese. After full-text evaluation and quality assessment, 26 articles were selected. Meta-analysis revealed that speed-sintering does not significantly affect the CIEDE2000-based translucency parameter, contrast ratio, three-point flexural strength, biaxial flexural strength, or fracture toughness of YSZ (p < 0.01) compared to conventional sintering. However, the CIELab-based translucency parameter of conventionally sintered YSZ is higher than that of speed-sintered YSZ. The descriptive analysis indicated that speed-sintering does not affect the hardness of YSZ compared to that of conventionally sintered YSZ. The results indicate that speed-sintering is suitable for preparing YSZ for dental restorations.

Preliminary Study on the Optimization of Femtosecond Laser Treatment on the Surface Morphology of Lithium Disilicate Glass-Ceramics and Highly Translucent Zirconia Ceramics.

All-ceramic restorations have become increasingly popular in dentistry. Toward ensuring that these restorations adhere to the tooth structure, this study determines the optimal femtosecond laser (FL) treatment parameters for lithium disilicate glass-ceramics and highly translucent zirconia ceramics with respect to surface morphology. For both the ceramics, the following surface conditions were investigated: (1) as-sintered; (2) Al2O3 sandblasted; (3) FL treatment (dot pattern with line distances of 14, 20, and 40 µm); (4) FL treatment (crossed-line pattern with a line distance of 20 and 40 µm). Surface roughness parameters were estimated using a 3D confocal laser microscope; microstructures were analyzed using a scanning electron microscope. Peak fluence (Fpeak) values of 4 and 8 J/cm2 and irradiation numbers (N) of 20 and 10 shots were selected to create dot patterns in highly translucent zirconia and lithium disilicate glass-ceramics, respectively. Furthermore, Fpeak = 8 J/cm2 and N = 20 shots were chosen to obtain crossed-line patterns in both ceramics. Our results show that lithium disilicate glass-ceramics and highly translucent zirconia exhibit a similar surface morphology under each of the surface treatment conditions. Therefore, FL irradiation of dot or crossed-line patterns (at a distance of 20 and 40 µm) are potential candidates for future investigations.

Fiber-Shape Na3V2(PO4)2F3@N-Doped Carbon as a Cathode Material with Enhanced Cycling Stability for Na-Ion Batteries.

To overcome intrinsic low electronic conductance, delicately designed fiber-shape Na3V2(PO4)2F3@N-doped carbon composites (NVPF@C) have been prepared for boosting Na-storage performance. This distinctive interlinked three-dimensional network structure can effectively facilitate electron/Na-ion transportation by decreasing the NVPF particle size to shorten the ionic diffusion paths and introducing a conducting N-doping carbon scaffold to improve electronic conductivity. Benefiting from the favorable structural design and fascinating reaction kinetics, the modified NVPF@C material demonstrates superior sodium-storage performance with 109.5 mAh g-1 high reversible capacity at a moderate current of 0.1 C, excellent rate tolerance of 78.9 mAh g-1 at a high rate of 30 C, and gratifying long-term cyclability (87.8% capacity retention after 1000 cycles at 20 C; 83.4% capacity retention after 1500 round trips at a ultrahigh rate of 50 C). The fascinating electrochemical performance remains stable when NVPF@C was examined as the cathode material for a full cell, suggesting the fiber-shape NVPF@C as one of the most promising applicable materials for sodium-ion batteries. Moreover, the approach of the three-dimensional conductive network by electrospinning is proposed as a strategy of efficiency and promising prospect to enhance the electrochemical property of other materials for sodium-ion batteries.

A highly efficient electrocatalyst based on double perovskite cobaltites with immense intrinsic catalytic activity for water oxidation.

High temperature electrocatalysts based on double perovskite cobaltites that are typically employed in proton ceramic fuel cells and electrolyzers are exploited here for room temperature water oxidation. The double perovskites are assessed by the RctCdl product and we show that their intrinsic catalytic activities exceed that of IrO2.

Hierarchical Nitrogen-Doped Porous Carbon Microspheres as Anode for High Performance Sodium Ion Batteries.

Sodium ion batteries (SIBs) have been considered as a promising alternative to lithium ion batteries (LIBs) for large scale energy storage in the future. However, the commercial graphite anode is not suitable for SIBs because of its low Na+ ions storage capability and poor cycling stability. Recently, another alternative as anode for SIBs, amorphous carbon materials, have attracted tremendous attention because of their abundant resource, nontoxicity, and most importantly, stability. Here, N-doped hierarchical porous carbon microspheres (NHPCS) derived from Ni-MOF have been prepared and used as anode for SIBs. Benefiting from the open porous structure and expanded interlayer distance, the diffusion of Na+ is greatly facilitated and the Na+ storage capacity is significantly enhanced concurrently. The NHPCS exhibit high reversible capacity (291 mA h g-1 at current of 200 mA g-1), excellent rate performance (256 mA h g-1 at high current of 1,000 mA g-1), and outstanding cycling stability (204 mA h g-1 after 200 cycles).

Ta3N5/Co(OH)x composites as photocatalysts for photoelectrochemical water splitting.

Ta3N5 nanotubes (NTs) were obtained from nitridation of Ta2O5 NTs, which were grown directly on Ta foil through a 2-step anodization procedure. With Co(OH)x decoration, a photocurrent density as high as 2.3 mA cm-2 (1.23 V vs. NHE) was reached under AM1.5G simulated solar light; however, the electrode suffered from photocorrosion. More stable photoelectrochemical (PEC) performance was achieved by first loading Co(OH)x, followed by loading cobalt phosphate (Co-Pi) as double co-catalysts. The Co(OH)x/Co-Pi double co-catalysts may act as a hole storage layer that slows down the photocorrosion caused by the accumulated holes on the surface of the electrode. A "waggling" appearance close to the "mouth" of Ta2O5 NTs was observed, and may indicate structural instability of the "mouth" region, which breaks into segments after nitridation and forms a top layer of broken Ta3N5 NTs. A unique mesoporous structure of the walls of the Ta3N5 NTs, which is reported here the first time, is also a result of the nitridation process. We believe that the mesoporous structure makes it difficult for the nanotubes to be fully covered by the co-catalyst layer, hence rationalizing the remaining degradation by photocorrosion.

Activated Amorphous Carbon With High-Porosity Derived From Camellia Pollen Grains as Anode Materials for Lithium/Sodium Ion Batteries.

Carbonaceous anode materials are commonly utilized in the energy storage systems, while their unsatisfied electrochemical performances hardly meet the increasing requirements for advanced anode materials. Here, activated amorphous carbon (AAC) is synthesized by carbonizing renewable camellia pollen grains with naturally hierarchical structure, which not only maintains abundant micro- and mesopores with surprising specific surface area (660 m2 g-1), but also enlarges the interlayer spacing from 0.352 to 0.4 nm, effectively facilitating ions transport, intercalation, and adsorption. Benefiting from such unique characteristic, AAC exhibits 691.7 mAh g-1 after 1200 cycles at 2 A g-1, and achieves 459.7, 335.4, 288.7, 251.7, and 213.5 mAh g-1 at 0.1, 0.5, 1, 2, 5 A g-1 in rate response for lithium-ion batteries (LIBs). Additionally, reversible capacities of 324.8, 321.6, 312.1, 298.9, 282.3, 272.4 mAh g-1 at various rates of 0.1, 0.2, 0.5, 1, 2, 5 A g-1 are preserved for sodium-ion batteries (SIBs). The results reveal that the AAC anode derived from camellia pollen grains can display excellent cyclic life and superior rate performances, endowing the infinite potential to extend its applications in LIBs and SIBs.

Solid-state photoelectrochemical cell with TiO2 nanotubes for water splitting.

We have fabricated and tested a photoelectrochemical (PEC) cell where the aqueous electrolyte has been replaced by a proton conducting hydrated Nafion® polymer membrane. The membrane was sandwiched between a TiO2-based photoanode and a Pt/C-based cathode. The performance was tested with two types of photoanode electrodes, a thermally prepared TiO2 film on Ti foil (T-TiO2) and a nanostructured TiO2 films in the form of highly ordered nanotubes (TNT) of different lengths. Firstly, photovoltammetry experiments were conducted under asymmetric conditions, where the anode was immersed in deionized water, while the cathode was kept in ambient air. The results showed a high incident photon-to-current efficiency (IPCE) of 19% under unassisted conditions (short-circuit, 0 V vs. cathode) with short TNT (ca. 1 µm) under 4 mW cm-2 illumination with UV-A rich light. Secondly, the deionized water was replaced by 0.5 M Na2SO4 and now the performance was higher with longer nanotubes, assigned to increased ionic conductivity inside the tubes. An unassisted (0 V) IPCE of 33% was achieved with nanotubes of ca. 8 µm. The presented solid-state PEC cell minimizes the electrode distance and volume of the device, and provides a way towards compact practical applications in solar water splitting.