In situ incorporation of nanostructured antimony in an N-doped carbon matrix for advanced sodium-ion batteries

Herein, a facile one-step and solvent-free pyrolysis method was developed to control the synthesis of nanostructured Sb embedded in an N-doped carbon matrix (Sb@G x N y -T, where T, G x and N y denote the annealing temperature and the mass (g) of glucose and NH 4 Cl used in the process, respectively). By adjusting these parameters, hybrid architectures can be in situ constructed, including hollow Sb embedded in holeless carbon matrixes (Sb@G 0.25 N 0.5 -950) and Sb nanoplates embedded in holey carbon matrixes (Sb@G 0.25 N 0.25 -950). Our findings suggest that the formation of diverse nanostructures closely relate to the sublimation and evaporation of Sb, and the structural remold of liquid Sb by surface tension. Benefitting from the unique structural features, these optimized electrodes show highly reversible sodium storage with high specific capacities and good cycling stability. More importantly, this strategy can be further extended to other material systems, such as Sn- and SnO 2 nanodots embedded in a holey carbon matrix. This work presents a new scalable methodology to confine/remold nanostructured materials in a carbon matrix which allows for the future design of functional materials with tunable composition and architecture

Unraveling the effect of salt chemistry on long-durability high-phosphorus-concentration anode for potassium ion batteries

Phosphorus-based anode materials are of considerable interest for grid-scale energy storage systems due to their high theoretical capacity. Nevertheless, the low electrical conductivity of P, large volume changes during cycling, and highly-reactive phosphide surface are hindering their potential applications. Herein, outstanding long-term cycling stability with high retained potassium storage capacity (213.7 mA h g−1over 2000 cycles) was achieved via the introduction of an alternative potassium bis(fluorosulfonyl)imide (KFSI) salt and by using a layered compound (GeP5) with a high phosphorus concentration as anode material. Fourier transform infrared spectroscopic mapping results suggest that KFSI salt helps to form an uniform solid electrolyte interphase (SEI) layer and reduces the side reactions at the electrode/electrolyte interface, thus enhancing the cycling performance. In-operando synchrotron X-ray diffraction analysis has revealed the synergistic reaction mechanisms of the K-P and K-Ge reactions. These findings indicate the enormous potential of phosphorus-based anodes for high-performance potassium ion batteries and can attract broad interest for regulating the SEI layer formation through manipulating the salt chemistry

Electronic health record–based absolute risk prediction model for esophageal cancer in the Chinese population: model development and external validation

Background: China has the largest burden of esophageal cancer (EC). Prediction models can be used to identify high-risk individuals for intensive lifestyle interventions and endoscopy screening. However, the current prediction models are limited by small sample size and a lack of external validation, and none of them can be embedded into the booming electronic health records (EHRs) in China. Objective: This study aims to develop and validate absolute risk prediction models for EC in the Chinese population. In particular, we assessed whether models that contain only EHR-available predictors performed well. Methods: A prospective cohort recruiting 510,145 participants free of cancer from both high EC-risk and low EC-risk areas in China was used to develop EC models. Another prospective cohort of 18,441 participants was used for validation. A flexible parametric model was used to develop a 10-year absolute risk model by considering the competing risks (full model). The full model was then abbreviated by keeping only EHR-available predictors. We internally and externally validated the models by using the area under the receiver operating characteristic curve (AUC) and calibration plots and compared them based on classification measures. Results: During a median of 11.1 years of follow-up, we observed 2550 EC incident cases. The models consisted of age, sex, regional EC-risk level (high-risk areas: 2 study regions; low-risk areas: 8 regions), education, family history of cancer (simple model), smoking, alcohol use, BMI (intermediate model), physical activity, hot tea consumption, and fresh fruit consumption (full model). The performance was only slightly compromised after the abbreviation. The simple and intermediate models showed good calibration and excellent discriminating ability with AUCs (95% CIs) of 0.822 (0.783-0.861) and 0.830 (0.792-0.867) in the external validation and 0.871 (0.858-0.884) and 0.879 (0.867-0.892) in the internal validation, respectively. Conclusions: Three nested 10-year EC absolute risk prediction models for Chinese adults aged 30-79 years were developed and validated, which may be particularly useful for populations in low EC-risk areas. Even the simple model with only 5 predictors available from EHRs had excellent discrimination and good calibration, indicating its potential for broader use in tailored EC prevention. The simple and intermediate models have the potential to be widely used for both primary and secondary prevention of EC

In situ incorporation of nanostructured antimony in an N-doped carbon matrix for advanced sodium-ion batteries

Herein, a facile one-step and solvent-free pyrolysis method was developed to control the synthesis of nanostructured Sb embedded in an N-doped carbon matrix (Sb@G x N y -T, where T, G x and N y denote the annealing temperature and the mass (g) of glucose and NH 4 Cl used in the process, respectively). By adjusting these parameters, hybrid architectures can be in situ constructed, including hollow Sb embedded in holeless carbon matrixes (Sb@G 0.25 N 0.5 -950) and Sb nanoplates embedded in holey carbon matrixes (Sb@G 0.25 N 0.25 -950). Our findings suggest that the formation of diverse nanostructures closely relate to the sublimation and evaporation of Sb, and the structural remold of liquid Sb by surface tension. Benefitting from the unique structural features, these optimized electrodes show highly reversible sodium storage with high specific capacities and good cycling stability. More importantly, this strategy can be further extended to other material systems, such as Sn- and SnO 2 nanodots embedded in a holey carbon matrix. This work presents a new scalable methodology to confine/remold nanostructured materials in a carbon matrix which allows for the future design of functional materials with tunable composition and architecture

Coupling Topological Insulator SnSb2Te4 Nanodots with Highly Doped Graphene for High-Rate Energy Storage

Topological insulators have spurred worldwide interest, but their advantageous properties have scarcely been explored in terms of electrochemical energy storage, and their high-rate capability and long-term cycling stability still remain a significant challenge to harvest. p-Type topological insulator SnSb2Te4 nanodots anchoring on few-layered graphene (SnSb2Te4/G) are synthesized as a stable anode for high-rate lithium-ion batteries and potassium-ion batteries through a ball-milling method. These SnSb2Te4/G composite electrodes show ultralong cycle lifespan (478 mAh g−1 at 1 A g−1 after 1000 cycles) and excellent rate capability (remaining 373 mAh g−1 even at 10 A g−1) in Li-ion storage owing to the rapid ion transport accelerated by the PN heterojunction, virtual electron highways provided by the conductive topological surface state, and extraordinary pseudocapacitive contribution, whose excellent phase reversibility is confirmed by synchrotron in situ X-ray powder diffraction. Surprisingly, durable lifespan even at practical levels of mass loading (\u3e10 mg cm−2) for Li-ion storage and excellent K-ion storage performance are also observed. This work provides new insights for designing high-rate electrode materials by boosting conductive topological surfaces, atomic doping, and the interface interaction

Coupling Topological Insulator SnSb2Te4 Nanodots with Highly Doped Graphene for High-Rate Energy Storage

Topological insulators have spurred worldwide interest, but their advantageous properties have scarcely been explored in terms of electrochemical energy storage, and their high-rate capability and long-term cycling stability still remain a significant challenge to harvest. p-Type topological insulator SnSb2Te4 nanodots anchoring on few-layered graphene (SnSb2Te4/G) are synthesized as a stable anode for high-rate lithium-ion batteries and potassium-ion batteries through a ball-milling method. These SnSb2Te4/G composite electrodes show ultralong cycle lifespan (478 mAh g−1 at 1 A g−1 after 1000 cycles) and excellent rate capability (remaining 373 mAh g−1 even at 10 A g−1) in Li-ion storage owing to the rapid ion transport accelerated by the PN heterojunction, virtual electron highways provided by the conductive topological surface state, and extraordinary pseudocapacitive contribution, whose excellent phase reversibility is confirmed by synchrotron in situ X-ray powder diffraction. Surprisingly, durable lifespan even at practical levels of mass loading (\u3e10 mg cm−2) for Li-ion storage and excellent K-ion storage performance are also observed. This work provides new insights for designing high-rate electrode materials by boosting conductive topological surfaces, atomic doping, and the interface interaction

In Situ Synchrotron X-Ray Absorption Spectroscopy Studies of Anode Materials for Rechargeable Batteries

Taking advantage of a high-flux light source, synchrotron X-ray absorption spectroscopy (XAS) beamline is able to perform in situ/ex situ, element-selective, and qualitative/quantitative experiments to elucidate electrochemical reaction mechanisms of batteries accurately and efficiently. In situ synchrotron XAS probes dynamic electronic and local atomic structure information, including valence state, charge transfer, local geometry and symmetry, bond number/length/type and disorder degree, of target elements of significance during battery operation, which facilitates to promote the development of rechargeable batteries by building accurate structure-performance relationships fundamentally. In this review, the basic principles for XAS are briefly introduced, design strategies for in situ XAS experiments are proposed, salient in situ XAS studies of battery anodes are summarized, and current challenges and future opportunities based on XAS measurements are also outlined