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An artificial “salt-in-polymer” SEI was constructed on the surface of Li-MSiOx particles to maintain the structural integrity and inhibit the parasitic reaction at the electrode/electrolyte interface during cycling.

Micrometre-sized electrode materials have distinct advantages for battery applications in terms of energy density, processability, safety and cost. For the silicon monoxide anode that undergoes electrochemical alloying reaction with Li, the Li (de)intercalation by micron-sized active particles usually accompanies with a large volume variation, which pulverizes the particle structure and leads to rapidly faded storage performance. In this work, we proposed to stabilize the electrochemistry vs. Li of the micron-SiOx anode by forming a rigid-flexible bi-layer coating on the particle surface. The coating consists of pyrolysis carbon as the inner layer and polydopamine as the outer layer. While the inner layer guarantees high structural rigidity at particle surface and provides efficient pathway for electron conduction, the outer layer shows high flexibility for maintaining the integrity of micrometre-sized particles against drastic volume variation, and together they facilitate formation of stable solid electrolyte interface on the SiOx particles. A composite anode prepared by mixing the coated micron-SiOx with graphite delivered improved Li storage performance, and promised a high-capacity, long-life LiFePO4/SiOx-graphite pouch cell. Our strategy provides a general and feasible solution for building high-energy rechargeable batteries from micrometre-sized electrode materials with significant volume variation.

Microsized SiOx has been vigorously investigated as an advanced anode material for next-generation lithium-ion batteries. However, its practical application is seriously hampered by its huge volume variation during the repeated (de)lithiation process, which destroys the microparticle structure and results in rapid capacity fading. Herein, we propose the usage of trans-difluoroethylene carbonate (DFEC) as an electrolyte additive to maintain the structural integrity of microsized SiOx with a uniform carbon layer (SiOx@C). Compared with ethylene carbonate and fluoroethylene carbonate, DFEC has lower lowest unoccupied molecular orbital energy and higher reduction potential, which is easily reduced and promotes the in situ formation of a more stable LiF-rich solid electrolyte interphase (SEI) on the surface of anode materials. The LiF-rich SEI exhibits enhanced mechanical rigidity and ionic conductivity, thus enabling the microsized SiOx@C anodes' excellent lithium storage stability and high average Coulombic efficiency.

Metal-ion batteries, especially lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and potassium-ion batteries (PIBs), have emerged as promising electronic devices for energy conversion and...

Single-crystalline Ni-rich cathode (SC-NCM) has attracted increasing interest owing to its greater capacity retention in advanced solid-state lithium batteries (SSLBs), while suffers from severe interfacial instability during cycling. Here, via atomic layer deposition, Li

Carbon-coated SiOx microparticles (SiOx/C) demonstrate attractive potential for anode use in high-energy-density lithium-ion batteries due to high capacity and proper cycling stability. However, the excessive irreversible consumption of Li ions during the initial cycling remains a serious challenge arising from the limited lithium in full cells. Here, we endow SiOx/C anode with high initial Coulombic efficiency using the chemical pre-lithiation strategy. The lithium silicate is uniformly pregenerated in SiOx/C microparticles, which could effectively counteract the irreversible consumption of Li ions and avoid the complicated pre-lithiation process. Moreover, this strategy guarantees the structural integrity and processability of anode materials because of the homogeneous Li-organic complex solution pre-lithiation and high-temperature calcination process. The obtained SiOx/C microparticles can be applied as anode materials by directly mixing with commercial graphite, which demonstrates proper specific capacity, high initial Coulombic efficiency, and excellent cycling performance. Furthermore, the pouch cells using LiNi0.8Co0.1Mn0.1O2 cathodes and the as-prepared anodes exhibit high energy density (301 Wh kg-1) and satisfactory cycling stability (93.3% capacity retention after 100 cycles).

Li‐based secondary batteries are now attracting soaring research attention as a promising energy storage system with high energy density for commercial applications. However, the high‐energy systems meanwhile are causing serious concerns on safety issues due to unstable interfaces on both cathodes and anodes. To improve interphase stability upon extended cycles, surface fluorinated treatment becomes highly desirable due to its unique capability in modulating the chemistry of electrode/electrolyte interface to ensure a stable electrochemical performance. Accordingly, it is essential that a deeper understanding on the solid electrolyte interphase (SEI), especially the role of fluorine‐containing components, is demanded to guide the interface design. This review begins with an introduction to the fundamental knowledge on the structure of SEI with focus on the unique physiochemical properties of fluorides. Detailed discussions are then taken on the control strategies for a reliable construction of fluoride‐based interfaces, which typically includes the surface coating of metal fluorides on cathodes and ex situ/in situ fluorination on lithium, based on which the structure–performance relationship is elaborated to inspire a rational interface engineering. Finally, perspectives are provided to give insights into the possible research directions of fluorinated SEI for further development of rechargeable Li batteries.

Background We defined large-volume lymph node metastasis (L-VLNM) as more than five lymph node metastases (LNMs) or any lymph node with a diameter of 2 mm or greater in any case of papillary thyroid cancer (PTC). This study investigated risk factors for the development of L-VLNM in PTC with meta-analysis.Methods Articles published until July 2021 on clinicopathological factors of L-VLNM in PTC were searched in electronic databases (PubMed, Web of Science (WOS), Embase, Cochrane, Wanfang Data and Chinese National Knowledge Infrastructure (CNKI)) to identify studies based on predefined criteria. Statistical analysis was performed using STATA 14.0. The outcomes were clinical and pathologic factors for L-VLNM, and the individual and pooled odds ratios (ORs) with 95% confidence intervals (CIs) of each outcome were analysed by fixed-/random-effects models. Egger’s test was used to assess publication bias in the publications. This study is registered with PROSPERO (CRD 42020213831).Results Twelve studies included 10806 patients in total. Meta-analysis revealed that an increased risk of L-VLNM was associated with male sex (OR=2.20, 95% CI=1.63–2.97, P), ageOR=2.34, 95% CI=1.36–4.02, P), tumour diameter>1 cm (OR=3.99, 95% CI=3.45–4.62, P), extrathyroidal extension (OR=2.42, 95% CI=1.90–2.82, P), capsule invasion (OR=3.62, 95% CI=1.44–9.06, P) and multifocality (OR=2.02, 95% CI=1.47–2.77, P). Hashimoto’s thyroiditis (HT; OR=0.82, 95% CI=0.60–1.11, P=0.03) was not associated with L-VLNM.Conclusions Male sex, age 1 cm, extrathyroidal extension, capsule invasion and multifocality were risk factors for L-VLNM, HT was not a risk factor.

Silicon (Si) has been considered as one of the most promising anodes in secondary high-energy rechargeable lithium-ion batteries (LIBs) owing to its high theoretical specific capacity and abundant reserves, whereas it suffers from an unstable solid electrolyte interphase (SEI) film and dramatic volume expansion. Herein, in situ electrochemical atomic force microscopy (AFM) and visual videos were used to reveal the interphasial properties of SEI film and anisotropic dynamics upon lithiation/delithiation processes on the single-crystalline Si electrodes with different crystal plane orientations. Lithiation of Si (111) prefer to grow along the direction in the XY plane with the shape of oriented rods, in contrast, that of Si (100) form cone-like structure with the axial direction of perpendicular to the (100) surface. Quantitative dynamic processes elucidate the preferable reversibility in Si (111) system, revealing the corresponding structure-reactivity correlations.

Solid-state batteries provide a safe and high energy density solution to next-generation energy storage devices. However, unsatisfactory power capability and cycling stability raised from lithium diffusion resistance and catalytic reaction at the electrode/electrolyte interface critically restrict their development. In this study, these interfacial issues are ameliorated by LiBO2 coating to achieve the successful implementation of nickel-rich LiNi0.6Co0.2Mn0.2O2 in poly(ether-acrylate) based solid-state batteries. The continuous coating acts not only as a physical barrier hindering the decomposition of polymer electrolyte but also as a buffer layer promoting lithium diffusion across the space charge layer owing to its electronic insulativity and ionic conductivity. In consequence, the LiBO2 coated nickel-rich cathode delivers superior cycling stability with a capacity retention of 84.3% during 150 cycles at 0.5C, remarkably improved lithium diffusion kinetics with an order of magnitude increase in apparent diffusion coefficient and prominent power performance with 97 mA h g−1 at 2C. The effectiveness of inserting such functional interlayer emphasizes the essentiality of interfacial chemistry in building high-performance solid-state Li metal batteries.

BACKGROUND: Whether the lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) should be dissected is still controversial. This meta-analysis aimed to assess the risk factors for LN-prRLN metastasis in papillary thyroid carcinoma (PTC). METHODS: We retrieved relevant studies published before May 2020 from the Wanfang Data, CNKI, PubMed, Embase, Web of Science and Cochrane Library databases. Heterogeneity was assessed with the Q-test and inconsistency index and sensitivity analysis and subgroup analysis were then used to find the source of heterogeneity. Begg test and generate a funnel chart to assess publication bias. RESULTS: We retrieved 236 articles, 14 articles were selected as the subjects of our research. Fourteen studies involving 10,580 patients were analysed in this study. The LN-prRLN metastasis rate was 9.22% (975/10,580). The results of the meta-analysis showed that sex (P1 cm, multifocality, capsular invasion or extrathyroidal extension, and VIa-LN metastasis or LLN metastasis in PTC patients were significant risk factors for predicting LN-prRLN metastasis. B ultrasound and CT scans are expected to predict LN-prRLN metastasis in the future. REGISTRATION: This research is registered on the PROSPERO website (registration number: CRD42020200898).

Background: The prognostic significance of extranodal extension in papillary thyroid cancer remains controversial. Methods: Seven hundred and thirty-eight PTC patients were enrolled in the study from January 2016 to December 2019. Patients were dichotomized with or without ENE. Univariate and multivariate logistic analyses were used to compare differences between the two groups. Kaplan-Meier (K-M) curve and propensity score matching analysis were used for recurrence-free survival comparison. Result: Thirty patients (4.07%) had associated extranodal extension. Univariate analysis demonstrated age, tumor size, extrathyroidal extension, nodal staging to be associated with ENE. Further logistic regression analysis showed age, extrathyroidal extension and nodal staging remained statistically significant. Evaluation of K-M curves demonstrated a statistically significant difference was found between two groups before and after propensity score matching. Conclusions: Age≥55years, extrathyroidal extension, and lateral cervical lymph node metastasis have been identified as independent risk factors of ENE. PTC patients with ENE have worse recurrence-free survival. Funding: This work is supported by Science Research Program of Hangzhou(20180533B39), the Project of Medical Scientific and Technology Program in Hangzhou (grant number A20200432), and the Medical and Health Research Program of Zhejiang Province (2019RC240). Declaration of Interest: The authors declare no conflict of interests. Ethical Approval: The present study was approved by the Ethics Committee of our institution (Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine).

Carbon-coated SiO

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C═N groups, C═O groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g-1. The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.

In this work, nitrogen-doped LaNiO3 perovskite was prepared and studied, for the first time, as a bifunctional electrocatalyst for oxygen cathode in a rechargeable lithium–oxygen battery. N doping was found to significantly increase the Ni3+ contents and oxygen vacancies on the bulk surface of the perovskite, which helped to promote the oxygen reduction reaction and oxygen evolution reaction of the cathode and, therefore, enabled reversible Li2O2 formation and decomposition on the cathode surface. As a result, the oxygen cathodes loaded with N-doped LaNiO3 catalyst showed an improved electrochemical performance in terms of discharge capacity and cycling stability to promise practical Li–O2 batteries.

Micron-sized SiOx particles, owing to their distinct advantages in energy density, processability and cost, have shown promises in Li-ion batteries. However, the huge volume variation of micron-SiOx raises many issues including overgrowth of solid electrolyte interphase (SEI) and pulverization of bulk, which accounts for continuously faded storage performance during repeated Li uptake/release. To address above problems, we propose to stabilize the electrochemistry of micron-SiOx by building an integral interface with dynamically stable evolution on carbon-coated SiOx particles. The interface consists of Li polyacrylate nanolayer interfused with multiwalled carbon nanotubes. Both highly stretchable components maintain the structural integrity of micron-SiOx particles upon volume variation and coalesce the secondary particles in case pulverization occurs. The interface also enables injection of Li+/e– into micron-SiOx for sustaining the (de)lithiation, while restrains the overgrowth of SEI. Micron-SiOx particles protected by the integral interface have demonstrated, both in Li half and full cells, improved lithium storage properties in terms of capacity output and retention, Coulombic efficiency and rate capabilities. With this work, we tend to offer insights on interfacial engineering of micron-sized electrode materials with unstable chemical or structural evolution in practical batteries.

A highly conductive sulfur cathode is crucial for improving the kinetic performance of a Li-S battery. The encapsulation of sulfur in porous nanocarbons is expected to benefit the Li(+) migration, yet the e(-) conduction is still to be improved due to a low graphitization degree of a conventional carbon substrate, especially that pyrolyzed from carbohydrates or polymers. Aiming at facilitating the e(-) conduction in the cathode, here we propose to use ketjen black, a highly graphitized nanocarbon building block to form a conductive network for electrons in a biomass-derived, hierarchically porous carbon sponge by a easily scaled-up approach at a low cost. The specifically designed carbon host ensures a high loading and good retention of active sulfur, while also provides a faster electron transmission to benefit the lithiation/delithiation kinetics of sulfur. The sulfur cathode prepared from the carbon network shows excellent cycling and rate performance in a Li-S battery, rendering its practicality for emerging energy storage opportunities such as grids or automobiles.

Graphene-wrapped lithium-excess layered hybrid materials (Li(2)MnO(3)·LiMO(2), M = Mn, Ni, Co, hereafter abbreviated as LMNCO) have been synthesized and investigated as cathode materials for lithium-ion batteries. Cyclic voltammetry measurement shows a significant reduction of the reaction overpotential in benefit of the graphene conducting framework. The electrochemical impedance spectroscopy results reveal that the graphene can greatly reduce the cell resistance, especially the charge transfer resistance. Our investigation demonstrates that the graphene conducting framework can efficiently alleviate the polarization of pristine LMNCO material leading to an outstanding enhancement in cell performance and cycling stability. The superior electrochemical properties support the fine hybrid structure design by enwrapping active materials in graphene nanosheets for high-capacity and high-rate cathode materials.

To exploit the high energy density of lithium-sulfur batteries, porous carbon materials have been widely used as the host materials of the S cathode. Current studies about carbon hosts are more frequently focused on the design of carbon structures rather than modification of its properties. In this study, we use boron-doped porous carbon materials as the host material of the S cathode to get an insightful investigation of the effect of B dopant on the S/C cathode. Powder electronic conductivity shows that the B-doped carbon materials exhibit higher conductivity than the pure analogous porous carbon. Moreover, by X-ray photoelectron spectroscopy, we prove that doping with B leads to a positively polarized surface of carbon substrates and allows chemisorption of S and its polysulfides. Thus, the B-doped carbons can ensure a more stable S/C cathode with satisfactory conductivity, which is demonstrated by the electrochemical performance evaluation. The S/B-doped carbon cathode was found to deliver much higher initial capacity (1300 mA h g(-1) at 0.25 C), improved cyclic stability, and rate capability when compared with the cathode based on pure porous carbon. Electrochemical impedance spectra also indicate the low resistance of the S/B-doped C cathode and the chemisorption of polysulfide anions because of the presence of B. These features of B doping can play the positive role in the electrochemical performance of S cathodes and help to build better Li-S batteries.

Germanium is a promising high-capacity anode material for lithium ion batteries, but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. A double protection strategy to improve the electrode performance of Ge through the use of Ge@C core–shell nanostructures and reduced graphene oxide (RGO) networks has been developed. The as-synthesized Ge@C/RGO nanocomposite showed excellent cycling performance and rate capability in comparison with Ge@C nanoparticles when used as an anode material for Li ion batteries, which can be attributed to the electronically conductive and elastic RGO networks in addition to the carbon shells and small particle sizes of Ge. The strategy is simple yet very effective, and because of its versatility, it may be extended to other high-capacity electrode materials with large volume variations and low electrical conductivities.

An electronically conducting 3D network of reduced graphene oxide (RGO) was introduced into LiNi(1/3)Mn(1/3)Co(1/3)O(2) (LNMC) cathode material in a special nano/micro hierarchical structure. The rate test and cycling measurement showed that the hierarchical networks remarkably improve the high rate performance of LNMC electrode for lithium-ion batteries. The effect of RGO conducting networks on kinetic property was investigated by electrochemical impedance spectroscopy (EIS) and potentiostatic intermittent titration (PITT). The EIS results reveal that the RGO network greatly decreases the resistance of lithium batteries, especially the charge transfer resistance which can be attributed to the significantly improved conducting networks. The enhancement of apparent diffusion coefficient by the RGO conducting networks is shown by PITT. The power performance was found to be limited by the electrical conduction in the two-phase region, which can be greatly facilitated by the hierarchical RGO network together with carbon black. The as-obtained LNMC/RGO cathode exhibits an outstanding electrochemical property supporting the design idea of electronically conducting 3D networks for the high-energy and high-power lithium-ion batteries.