Vanadium-modified hard carbon spheres with sufficient pseudographitic domains as high-performance anode for sodium-ion batteries

Hard carbons are promising anode materials for sodium-ion batteries.To meet practical requirements,searching for durable and conductive carbon with a stable interface is of great importance.Here,we prepare a series of vanadiummodified hard carbon submicrospheres by using hydrothermal carbonization followed by high-temperature pyrolysis.Significantly,the introduction of vanadium can facilitate the nucleation and uniform growth of carbon spheres and generate abundant V-O-C interface bonds,thus optimizing the reaction kinetic.Meanwhile,the optimized hard carbon spheres modified by vanadium carbide,with sufficient pseudographitic domains,provide more active sites for Na ion migration and storage.As a result,the HC/VC-1300 electrode exhibits excellent Na storage performance,including a high capacity of 420 mAh g^(-1) at 50mA g^(-1) and good rate capability at 1 A g^(-1).This study proposes a new strategy for the synthesis of hard carbon spheres with high tap density and emphasizes the key role of pseudographitic structure for Na storage and interface stabilization.

A maturity model for blockchain adoption

Background:The rapid development of the blockchain technology and its various applications has rendered it important to understand the guidelines for adopting it.Methods:The comparative analysis method is used to analyze different dimensions of the maturity model,which is mainly based on the commonly used capability maturity model.Results:The blockchain maturity model and its adoption process have been discussed and presented.Conclusions:This study serves as a guide to institutions to make blockchain adoption decisions more systematically.

高电压氟磷酸钠钒纳米棒阵列实现高性能柔性钠离子电池

柔性钠离子电池(SIBs)在便携式和可穿戴设备中具有巨大的应用潜力,因为它们在特定情况下具有适用性和价格优势.在正极材料中,磷酸盐电极材料具有结构稳定性好、工作电位高和寿命长的优点.然而,由于对制造要求苛刻,反应复杂,以及柔性基材的缺失等问题,柔性磷酸盐电极材料的设计仍然是一个巨大的挑战.在此,我们报道了在柔性多孔碳纳米纤维上垂直生长的VO_(2)纳米片原位转化为三维氟磷酸钒钠纳米棒阵列(PCNF@NVOPF NR).PCNF@NVOPF NR实现了兼具柔性与高压正极电极的特点,并具有长期循环稳定性(4500次循环后容量保持率为87.6%).阵列结构可以确保快速的钠反应动力学和低界面电阻.此外,PCNF@NVOPF NR//PCNF@VO_(2)NS@C钠离子全电池表现出高能量和功率密度(220.5 W h kg^(-1)和9400 W kg^(-1)).这种用于柔性正极的材料设计策略可促进实用钠离子电池的商业化.

From computer vision to short text understanding: Applying similar approaches into different disciplines

With the development of IoT and 5G technologies,more and more online resources are presented in trendy multimodal data forms over the Internet.Hence,effectively processing multimodal information is significant to the development of various online applications,including e-learning and digital health,to just name a few.However,most AI-driven systems or models can only handle limited forms of information.In this study,we investigate the correlation between natural language processing(NLP)and pattern recognition,trying to apply the mainstream approaches and models used in the computer vision(CV)to the task of NLP.Based on two different Twitter datasets,we propose a convolutional neural network based model to interpret the content of short text with different goals and application backgrounds.The experiments have demonstrated that our proposed model shows fairly competitive performance compared to the mainstream recurrent neural network based NLP models such as bidirectional long short-term memory(Bi-LSTM)and bidirectional gate recurrent unit(Bi-GRU).Moreover,the experimental results also demonstrate that the proposed model can precisely locate the key information in the given text.