Unraveling the incompatibility mechanism of ethylene carbonate-based electrolytes in sodium metal anodes

Ethylene carbonate(EC)is widely used in lithium-ion batteries due to its optimal overall performance with satisfactory conductivity,relatively stable solid electrolyte interphase(SEI),and wide electrochemical window.EC is also the most widely used electrolyte solvent in sodium ion batteries.However,compared to lithium metal,sodium metal(Na)shows higher activity and reacts violently with EC-based electrolyte(NaPF_(6)as solute),which leads to the failure of sodium metal batteries(SMBs).Herein,we reveal the electrochemical instability mechanism of EC on sodium metal battery,and find that the com-bination of EC and NaPF_(6) is electrically reduced in sodium metal anode during charging,resulting in the reduction of the first coulombic efficiency,and the continuous consumption of electrolyte leads to the cell failure.To address the above issues,an additive modified linear carbonate-based electrolyte is provided as a substitute for EC based electrolytes.Specifically,ethyl methyl carbonate(EMC)and dimethyl carbon-ate(DMC)as solvents and fluoroethylene carbonate(FEC)as SEI-forming additive have been identified as the optimal solvent for NaFP_(6)based electrolyte and used in Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7))/Na batteries.The batter-ies exhibit excellent capacity retention rate of about 80%over 1000 cycles at a cut-off voltage of 4.3 V.

Enabling stable 4.6 V LiCoO_(2) cathode through oxygen charge regulation strategy

LiCoO_(2) is the preferred cathode material for consumer electronic products due to its high volumetric energy density. However, the unfavorable phase transition and surface oxygen release limits the practical application of LiCoO_(2)at a high-voltage of 4.6 V to achieve a higher energy density demanded by the market. Herein, both bulk and surface structures of LiCoO_(2)are stabilized at 4.6 V through oxygen charge regulation by Gd-gradient doping. The enrichment of highly electropositive Gd on LiCoO_(2) surface will increase the effective charge on oxygen and improve the oxygen framework stability against oxygen loss.On the other hand, Gd ions occupy the Co-sites and suppress the unfavorable phase transition and microcrack. The modified LiCoO_(2) exhibits superior cycling stability with capacity retention of 90.1% over 200 cycles at 4.6 V, and also obtains a high capacity of 145.7 m Ah/g at 5 C. This work shows great promise for developing high-voltage LiCoO_(2) at 4.6 V and the strategy could also contribute to optimizing other cathode materials with high voltage and large capacity, such as cobalt-free high-nickel and lithiumrich manganese-based cathode materials.

Malignant proliferative ependymoma of the neck with lymph node metastasis:A case report

BACKGROUND Malignant proliferating trichilemmal tumor(MPTT)is an infrequent malignant neoplasm originating from cutaneous appendages,with only a handful of documented cases.This report delineates a unique instance of MPTT situated in the neck,accompanied by lymph node metastasis.A comprehensive exposition of its clinical trajectory and imaging manifestation is presented,aiming to enhance comprehension and management of this atypical ailment.CASE SUMMARY Patient concerns:A 79-year-old male presented with a longstanding right neck mass persisting for over six decades,exhibiting recent enlargement over the past year.Diagnoses:Enhanced magnetic resonance imaging of the neck unveiled an elliptical mass on the right neck side,characterized by an ill-defined border and a heterogeneous signal pattern.The mass exhibited subdued signal intensity on T1-weighted imaging(T1WI)and a heterogeneous high signal on T2-weighted imaging(T2WI),interspersed with a lengthy T1 and T2 cystic signal motif.Close anatomical association with the submandibular gland joint was noted,and intravenous gadolinium diethylene triamine pentaacetic acid administration facilitated conspicuous enhancement.Substantial enhancement of the solid segment prompted an initial preoperative diagnosis of malignant nerve sheath tumor.However,post-surgery histopathological and immunohistochemical analysis conclusively confirmed the diagnosis as malignant hyperplastic external hair root sheath tumor.Intervention:Complete excision of the tumor was successfully executed.Outcomes:The patient experienced a favorable postoperative recovery.CONCLUSION Malignant proliferative trichilemmal tumor external hair root sheath tumor is a cystic-solid lesion,appearing as low signal on T1WI images or high signal on T2WI with enhancement of the solid component.Suspicions of malignancy are heightened when the tumor border is indistinct,tissue planes are breached,or when linear or patchy high signals are observed in the subcutaneous tissue on T1 liver acquisition with volume acceleration enhanced images along with intermediate signal on T2WI and restricted diffusion on diffusion-weighted imaging images.Strong consideration for malignancy should arise if there are signs of compromised adjacent tissue relationships or direct invasion evident on imaging.We have incorporated the above-mentioned content into the entire manuscript.

Endoleak management and postoperative surveillance following endovascular repair of internal carotid artery vascular diseases using Willis covered stent

Background:To report the clinical results and experiences of endoleak management and postoperative surveillance following endovascular repair of internal carotid artery vascular diseases(ICAVDs)using Willis covered stents.METHODS:Seventy-three patients with ICAVD who received Willis covered stent implantation between November 2013 and September 2018 were retrospectively reviewed.The clinical data of endoleak management and postoperative surveillance were analyzed.RESULTS:Seventy-three cases with ICAVD,including 57 aneurysms,11 carotid-cavernous sinus fistulas(CCF),and 5 surgical injuries,were all successfully installed with covered stents.Total isolation of ICAVDs was achieved in 59 patients(80.8%),and endoleaks were observed in 14 patients(19.2%).Of the 14 patients with endoleaks,12 had type I endoleaks and 2 had type II;13 had aneurysms and one had CCF.10 patients with type I endoleaks received balloon dilatation,and 7 of them underwent a second stent-graft implantation after then.One patient with type II endoleak received embolization of the branch artery,and another one received follow-up observation.Endoleaks resolved in 6 patients and were minimal in 5 patients after balloon dilatation or the second stent implantation.During the follow-up period,minor endoleaks spontaneously resolved in 4 patients and minimal endoleaks were still demonstrated in 4 patients without enlargement of residual lumen and rupture.CONCLUSIONS:Endoleaks are the major complication after endovascular repair of ICAVDs and represent one of the limitations of this procedure.Improving the understanding and management of endoleaks can be beneficial in the clinical setting,including the popularization and application of this technique.

电解液调控实现高电压高镍三元长循环稳定

为了满足500公里以上续航里程的苛刻要求,根据国家动力电池技术规划,对锂离子电池的能量密度提出了更高的要求,2025年达到400 Wh/kg,2030年达到500 Wh/kg.正极材料的选择对提高电池的能量密度非常关键.LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)因具有高比容量和高工作电势而在高能量密度锂离子电池领域备受关注[1,2].对于NCM811来说,Ni元素通过Ni^(2+)/Ni^(3+)和Ni^(3+)/Ni^(4+)氧化还原对贡献了大部分电容,并且随着充电截止电压的升高,提供的比容量增加,从而更高的能量密度可被获得.

高电压高镍三元锂离子电池电解液设计

LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)因具有高容量和相对低的成本,是高能量密度锂离子电池中最有前途的正极材料之一.然而,在高截止电压下,它仍然存在不可逆的容量衰减问题.主要原因是高电压加速了六氟磷酸锂与微量水的水解反应,产生副产物,如高腐蚀性HF,导致不稳定的正极-电解液界面和持续的不可逆相变.在这里,我们通过添加钛酸四丁酯和二氟草酸硼酸锂双重添加剂来改善传统的电解液,以形成一个稳定的富含Ti、B和F的界面层,从而消除不利的正极-电解液副反应并抑制有害相变.此外,钛酸四丁酯可以通过去除H_(2)O/HF来稳定电解液.在双重添加剂的协同作用下,NCM811在高电压下的循环稳定性得到明显增强.采用双添加剂的Li||NCM811电池在1 C和4.5 V的高截止电压下循环200次后具有86%的高容量保持率.该方法为设计锂离子电池的高电压电解液提供了参考.

Comparing a novel Catfish flow restoration device and the Solitaire stent retriever for thrombectomy revascularisation in emergent largevessel occlusion stroke:a prospective randomised controlled study

Background The Catfish stent retriever is a newly developed mechanical thrombectomy device for rapid recanalisation in emergent large vessel occlusion(ELVO)stroke.The current trial aimed to assess whether the Catfish stent retriever is non-inferior to the Solitaire stent retriever in terms of outcomes in ELVO stroke.Methods This was a randomised,prospective,parallel-group,multicentre,open-label,non-inferiority study conducted at 18 sites in China.The primary outcome was the proportion of cases with successful recanalisation(modified thrombolysis in cerebral infarction score of 2b or 3)following the procedure.Secondary efficacy outcomes included the National Institutes of Health Stroke Scale scores at 24 hours and 7 days or discharge if earlier,time from artery puncture to successful recanalisation and good clinical outcome(modified Rankin scale score≤2)at 90 days.Safety outcomes included symptomatic intracranial haemorrhage,all cause-death and severe adverse events at 90 days.Results Between 3 March 2019 and 5 June 2021,118 and 120 patients were randomly allocated to the Catfish and Solitaire groups,respectively.The primary endpoint after all endovascular procedures was non-inferior in the Catfish group(88.5%,100/113)than in the Solitaire group(87.7%,100/114),with a rate difference(RD)of 0.78%(95%CI-7.64 to-9.20;p=0.001).Sensitivity analysis only considering the per-protocol set also yielded similar results,with an RD of 0.83%(95%CI-7.03 to-8.70;p<0.001).Additionally,the proportions of cases with good clinical outcomes(47.8%vs 50.0%,p=0.739)and all-cause death rates(17.7%vs 18.8%,p=0.700)were similar in both groups at 90 days.Conclusions The Catfish stent retriever is an effective and safe device for endovascular recanalisation in ELVO stroke..

Tailoring electrolyte enables high-voltage Ni-rich NCM cathode against aggressive cathode chemistries for Li-ion batteries

The LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(Ni-rich NCM)cathode materials suffer from electrochemical performance degradation upon cycling due to detrimental cathode interface reactions and irreversible surface phase transition when operating at a high voltage(≥4.5 V).Herein,a traditional carbonate electrolyte with lithium difluoro(oxalato)borate(Li DFOB)and tris(trimethylsilyl)phosphate(TMSP)as dual additives that can preferentially oxidize and decompose to form a stable F,B and Si-rich cathode-electrolyte interphase(CEI)that effectively inhibits continual electrolyte decomposition,transition metal dissolves,surface phase transition and gas generation.In addition,TMSP also removes trace H_(2)O/HF in the electrolyte to increase the electrolyte stability.Owing to the synergistic effect of Li DFOB and TMSP,the Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) half cells exhibit the capacity retention 76.3%after 500 cycles at a super high voltage of 4.7 V,the graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)full cells exhibit high capacity retention of 82.8%after 500 cycles at 4.5 V,and Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)pouch cells exhibit high capacity retention 94%after 200 cycles at 4.5 V.This work is expected to provide an effective electrolyte optimizing strategy compatible with high energy density lithium-ion battery manufacturing systems.

Complete coverage path planning for an Arnold system based mobile robot to perform specific types of missions

We propose a contraction transformation algorithm to plan a complete coverage trajectory for a mobile robot to ac-complish specific types of missions based on the Arnold dynamical system. First, we construct a chaotic mobile robot by com-bining the variable z of the Arnold equation and the kinematic equation of the robot. Second, we construct the candidate sets including the initial points with a relatively high coverage rate of the constructed mobile robot. Then the trajectory is contracted to the current position of the robot based on the designed contraction transformation strategy, to form a continuous complete cov-erage trajectory to execute the specific types of missions. Compared with the traditional method, the designed algorithm requires no obstacle avoidance to the boundary of the given workplace, possesses a high coverage rate, and keeps the chaotic characteristics of the produced coverage trajectory relatively unchanged, which enables the robot to accomplish special missions with features of completeness, randomness, or unpredictability.

Internally inflated core-buffer-shell structural Si/EG/C composites as high-performance anodes for lithium-ion batteries

A watermelon-like internally inflated corebuffer-shell structural Si/electrochemically exfoliated graphene/C(Si/EG/C)composite is designed and prepared by the industrially established ball milling and spray drying method.Owing to numerous folds and voids in the EG filled between nano silicon and carbon shell,the volume fluctuations of silicon inside the Si/EG/C particles are buffered and lithium ions also could transport fast through the channels.With these advantages,the core-buffer-shell structural Si/EG/C composite demonstrates excellent electrochemical performance.The Si/EG/C anodes in half cells exhibit no degradation of the initial capacity(834 mA h g)after 100 cycles.Moreover,the Si/EG/C//LiCoOfull cells retain almost 100%of the initial discharge capacity after 500 cycles.These results highlight the potential applications of Si/EG/C in the next generation of Liion batteries.

Time-series surface water reconstruction method(TSWR)based on spatial distance relationship of multi-stage water boundaries

Spatiotemporal continuity of surface water datasets widely known for its significance in the surface water dynamic monitoring and assessments,are faced with drawbacks like cloud influence,which hinders the direct extraction of data from time-series remote sensing images.This study proposes a Time-series Surface Water Reconstruction method(TSWR).The initial stage of this method involves the effective use of remote sensing images to automatically construct multi-stage surface water boundaries based on Google Earth Engine(GEE).Then,we reconstructed regions the reconstruction of regions with missing water pixels using the distance relationship between the multi-stage water boundaries in previous and later periods.When applied to 10 large rivers around the world,this method yielded an overall accuracy of 98%for water extraction,an RMSE of 0.41 km2.Furthermore,time-series reconstruction tests conducted in 2020 on the Lancang and Danube rivers revealed a significant improvement in the image availability.These findings demonstrated that this method could not only be used to accurately reconstruct the surface water distribution missing water images,but also to depict a more pronounced time variation characteristic.The successful application of this method on GEE demonstrates its importance for use on large scales or in global studies.