Nd^(3+):GdScO_(3)晶体场能级及拟合分析

采用提拉法生长出了钕掺杂钪酸钆晶体(Nd^(3+):GdScO_(3)),通过低温吸收光谱和室温发射光谱,对其中Nd^(3+)的实验能级进行分析指认,确定了Nd^(3+):GdScO_(3)的66个实验Stark能级,拟合了其自由离子参数和晶体场参数,拟合均方根误差为13.17 cm^(–1).与Nd^(3+):YAP和Nd^(3+):YAG相比,Nd^(3+):GdScO_(3)的晶场强度较弱.弱的晶体场强度有可能是Nd^(3+):GdScO_(3)晶体具有优良激光特性的原因之一.本文数据集可在https://www.doi.org/10.57760/sciencedb.15702中访问获取.

Insights on advanced g‐C_(3)N_(4)in energy storage:Applications,challenges,and future

Graphitic carbon nitride(g‐C_(3)N_(4))is a highly recognized two‐dimensional semiconductor material known for its exceptional chemical and physical stability,environmental friendliness,and pollution‐free advantages.These remarkable properties have sparked extensive research in the field of energy storage.This review paper presents the latest advances in the utilization of g‐C_(3)N_(4)in various energy storage technologies,including lithium‐ion batteries,lithium‐sulfur batteries,sodium‐ion batteries,potassium‐ion batteries,and supercapacitors.One of the key strengths of g‐C_(3)N_(4)lies in its simple preparation process along with the ease of optimizing its material structure.It possesses abundant amino and Lewis basic groups,as well as a high density of nitrogen,enabling efficient charge transfer and electrolyte solution penetration.Moreover,the graphite‐like layered structure and the presence of largeπbonds in g‐C_(3)N_(4)contribute to its versatility in preparing multifunctional materials with different dimensions,element and group doping,and conjugated systems.These characteristics open up possibilities for expanding its application in energy storage devices.This article comprehensively reviews the research progress on g‐C_(3)N_(4)in energy storage and highlights its potential for future applications in this field.By exploring the advantages and unique features of g‐C_(3)N_(4),this paper provides valuable insights into harnessing the full potential of this material for energy storage applications.

In situ luminescence measurements of GaN/Al_(2)O_(3) film under different energy proton irradiations

Ion beam-induced luminescence(IBIL) experiments were performed to investigate the in situ luminescence of GaN/Al_(2)O_(3) at varying ion energies,which allowed for the measurement of defects at different depths within the material.The energies of H^(+)were set to 500 keV,640 keV and 2 MeV,the Bragg peaks of which correspond to the GaN film,GaN/Al_(2)O_(3) heterojunction and Al_(2)O_(3) substrate,respectively.A photoluminescence measurement at 250 K was also performed for comparison,during which only near band edge(NBE) and yellow band luminescence in the GaN film were observed.The evolution of the luminescence of the NBE and yellow band in the GaN film was discussed,and both exhibited a decrease with the fluence of H^(+).Additionally,the luminescence of F centers,induced by oxygen vacancies,and Cr^(3+),resulting from the ^(2)E →^(4)A_(2) radiative transition in Al_(2)O_(3),were measured using 2 MeV H^(+).The luminescence intensity of F centers increases gradually with the fluence of H^(+).The luminescence evolution of Cr^(3+)is consistent with a yellow band center,attributed to its weak intensity,and it is situated within the emission band of the yellow band in the GaN film.Our results show that IBIL measurement can effectively detect the luminescence behavior of multilayer films by adjusting the ion energy.Luminescence measurement can be excited by various techniques,but IBIL can satisfy in situ luminescence measurement,and multilayer structural materials of tens of micrometers can be measured through IBIL by adjusting the energy of the inducing ions.The evolution of defects at different layers with ion fluence can be obtained.

Polypyride intercalation boosting the kinetics and stability of V_(3)O_(7)·H_(2)O cathodes for aqueous zinc-ion batteries

V_(3)O_(7)·H_(2)O(VO)is a high capacity cathode material in the field of aqueous zinc ion batteries(AZIBs),but it is limited by slow ion migration and low electrical conductivity.In this paper,polypyridine(PPyd)intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation,which is noted VO-PPyd.The total density of states(TDOS)shows that after the pre-intercalation of PPyd,an intermediate energy level appears between the valence band and conduction band,which provides a step that can effectively reduce the band gap and enhance the electron conductivity.Furthermore,the density functional theory(DFT)results found that Zn^(2+)is more easily de-intercalated from the V-O skeleton,which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn^(2+).Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance(high specific capacity of 465 and 192 mA h g^(-1)at 0.2 and 10 A g^(-1),respectively)and long-term cycling performance(92.7%capacity retention rate after 5300 cycles),due to their advantages in structure and composition.More importantly,the energy density of VO-PPyd//Zn at 581 and 5806 W kg^(-1)is 375 and 247 W h kg^(-1),respectively.VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes,which makes it highly competitive in the field of high-performance cathode materials of AZIBs.

Nd^(3+)掺杂钙钛锆石(Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2))相变行为的研究

为研究钙钛锆石对放射性元素Am^(3+)的稳定固化作用,以Nd^(3+)为Am^(3+)的模拟元素,系统研究了高温固相法制备Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2)时,Nd^(3+)异价取代钙钛锆石晶格中Ca^(2+)位(0≤x≤1.0)所导致的相态演变行为。合成Ca_(1-x)Nd_(x)ZrTi_(2)O_(7+x/2)的XRD、Raman、BSE和EDS测试结果表明:钙钛锆石(Zirconolite)晶格对Nd^(3+)离子的固溶量可达70%(x=0.7),可有效实现对Am^(3+)模拟元素Nd^(3+)离子的固化。但随着Nd^(3+)掺杂量(x≤0.3)增加,Zirconolite-2M晶格中O^(2-)和Nd^(3+)的无序化程度逐渐增加、(Ca/Nd)-O键长逐渐变小,直至(x=0.4)引起Zr^(2+)、Ti^(4+)附近的O^(2-)配位数发生改变(ZrO7→ZrO8、TiO5→TiO6),Zirconolite-2M晶格结构开始向Zirconolite-4M转变。x=0.5时,陶瓷体完全转变为Zirconolite-4M晶格且O^(2-)和Nd^(3+)有序度重新变高、Ti—O键长增加;直至x=0.6、x=0.7时,陶瓷体仍为单一Zirconolite-4M结构,但晶格中O^(2-)和Nd^(3+)的有序度又逐渐降低,以至于在x=0.7陶瓷体亚晶格中微量Ca^(2+)、Zr^(4+)、Nd^(3+)离子占位转变为烧绿石(Pyrochlore)结构。而在0.8≤x≤0.9范围内,Zirconolite-4M结构完全消失,陶瓷体为多相共存状态(Pyrochlore、ZrTiO_(4)和Nd2(TiZr)_(4)O_(11)物相)。Nd^(3+)完全取代Ca^(2+)位(x=1.0)时,陶瓷体变为单一Nd2(TiZr)_(4)O_(11)固溶体相。陶瓷体晶粒的BSE和EDS分析证实了这种相变规律。

Yb^(3+)/Nd^(3+)掺杂对Sr_(9)Ga(PO_(4))_(7)∶Cr^(3+)发光性能的影响

近红外荧光粉由于其独特的物理特性和广阔的应用前景吸引了人们极大的研究兴趣。本文通过高温固相反应法合成Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+)近红外荧光粉,使用460 nm蓝光激发样品的发射波长位于833 nm,半峰宽为117 nm。随后引入稀土离子合成Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Yb^(3+)和Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Nd^(3+)近红外荧光粉。相比Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),460 nm蓝光激发的Sr_(9)Ga(PO_(4))_(7)∶0.8Cr^(3+),Yb^(3+)同时出现Cr^(3+)和Yb^(3+)特征发射峰,经过光谱分析和荧光寿命变化证明Cr^(3+)-Yb^(3+)存在能量传递通道,最高使Cr^(3+)-Yb^(3+)能量传递效率达80.2%,得益于Yb^(3+)卓越的热稳定性促使整体荧光光谱热稳定性提高约3.7倍。设计合成的Sr_(9)Ga(PO_(4))_7∶0.8Cr^(3+),Nd^(3+)样品调制出833,876,1 060 nm的多峰发射,显著拓宽了近红外光谱范围。最终,讨论了荧光粉在温度传感和无损检测领域的应用,证明该系列荧光粉具有广阔的应用前景。

Solid-state NMR study on sodium intercalation at low voltage window for Na_(3)V_(2)(PO_(4))_(3) as an anode

In-situ XRD,^(31)P NMR and ^(23)Na NMR were used to analyze the interaction behavior of Na_(3)V_(2)(PO_(4))_(3) at low voltage,and then a new intercalation model was proposed.During the transition from Na_(3)V_(2)(PO_(4))_(3) to Na_(4)V_(2)(PO_(4))_(3),Na ions insert into M1,M2 and M3 sites simultaneously.Afterwards,during the transition of Na_(4)V_(2)(PO_(4))_(3)to Na_(5)V_(2)(PO_(4))_(3),Na ions mainly insert into M3 site.

Robust Cross-Linked Na_(3)V_(2)(PO_(4))_(2)F_(3) Full Sodium-Ion Batteries

Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy density.However,it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity.Herein,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling stability.Benefited from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g^(-1)at 1 C,1 C=128 mA g^(-1))and remarkably improved long-term cycling stability with 93.9%capacity retention after 1000 cycles at 20 C.The energy density of 286.8 Wh kg^(-1)can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g^(-1)after 100 cycles at 1 C at 50℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.

Interfacial built-in electric field and crosslinking pathways enabling WS_(2)/Ti_(3)C_(2)T_(x) heterojunction with robust sodium storage at low temperature

Developing efficient energy storage for sodium-ion batteries(SIBs)by creating high-performance heterojunctions and understanding their interfacial interaction at the atomic/molecular level holds promise but is also challenging.Besides,sluggish reaction kinetics at low temperatures restrict the operation of SIBs in cold climates.Herein,cross-linking nanoarchitectonics of WS_(2)/Ti_(3)C_(2)T_(x) heterojunction,featuring built-in electric field(BIEF),have been developed,employing as a model to reveal the positive effect of heterojunction design and BIEF for modifying the reaction kinetics and electrochemical activity.Particularly,the theoretical analysis manifests the discrepancy in work functions leads to the electronic flow from the electron-rich Ti_(3)C_(2)T_(x) to layered WS_(2),spontaneously forming the BIEF and“ion reservoir”at the heterogeneous interface.Besides,the generation of cross-linking pathways further promotes the transportation of electrons/ions,which guarantees rapid diffusion kinetics and excellent structure coupling.Consequently,superior sodium storage performance is obtained for the WS_(2)/Ti_(3)C_(2)T_(x) heterojunction,with only 0.2%decay per cycle at 5.0 A g^(-1)(25℃)up to 1000 cycles and a high capacity of 293.5 mA h g^(-1)(0.1A g^(-1)after 100 cycles)even at-20℃.Importantly,the spontaneously formed BIEF,accompanied by“ion reservoir”,in heterojunction provides deep understandings of the correlation between structure fabricated and performance obtained.

Extending the solid solution range of sodium ferric pyrophosphate:Off‐stoichiometric Na_(3)Fe(2.5)(P_(2)O_(7))_(2)as a novel cathode for sodium‐ion batteries

Iron‐based pyrophosphates are attractive cathodes for sodium‐ion batteries due to their large framework,cost‐effectiveness,and high energy density.However,the understanding of the crystal structure is scarce and only a limited candidates have been reported so far.In this work,we found for the first time that a continuous solid solution,Na_(4−α)Fe_(2+α)_(2)(P_(2)O_(7))_(2)(0≤α≤1,could be obtained by mutual substitution of cations at center‐symmetric Na3 and Na4 sites while keeping the crystal building blocks of anionic P_(2)O_(7) unchanged.In particular,a novel off‐stoichiometric Na_(3)Fe(2.5)(P_(2)O_(7))_(2)is thus proposed,and its structure,energy storage mechanism,and electrochemical performance are extensively investigated to unveil the structure–function relationship.The as‐prepared off‐stoichiometric electrode delivers appealing performance with a reversible discharge capacity of 83 mAh g^(−1),a working voltage of 2.9 V(vs.Na^(+)/Na),the retention of 89.2%of the initial capacity after 500 cycles,and enhanced rate capability of 51 mAh g^(−1)at a current density of 1600 mA g^(−1).This research shows that sodium ferric pyrophosphate could form extended solid solution composition and promising phase is concealed in the range of Na_(4−α)Fe_(2+α)_(2)(P_(2)O_(7))_(2),offering more chances for exploration of new cathode materials for the construction of high‐performance SIBs.

Sb_(2)S_(3)/石墨烯负极材料的制备及其储钠性能研究

钠离子电池(sodium-ion batteries,SIBs)具有成本低的潜在优势,有望成为替代锂离子电池(lithium ion batteries,LIBs)的储能设备。为提升钠离子电池的性能,开发出适应钠离子脱嵌的负极材料尤为重要。硫化锑(Sb_(2)S_(3))因其理论比容量高被认为是较好的钠离子电池负极材料。本文使用简单水热法将Sb_(2)S_(3)与石墨烯复合,制备Sb_(2)S_(3)/石墨烯复合材料(Sb_(2)S_(3)/Gr)。结果表明:Sb_(2)S_(3)/Gr作为钠离子电池负极时,不仅表现出良好的电导率(3.5×10~(-3)S/cm)和钠离子扩散速率(4.853×10~(-13)cm~2/s),而且在0.5 A/g的电流密度下,首圈库伦效率为76.27%,经150次循环后的比容量稳定在488 m A·h/g,表现出较高的比容量。Sb_(2)S_(3)/Gr复合材料表现出了极大的应用潜力,为高性能钠离子电池负极材料的研发提供了一定的参考价值。

P2X7R过表达的巨噬细胞MSU晶体诱导痛风炎症反应过程中IL-1β、TNF-α、NLRP3表达观察

目的观察嘌呤能受体P2X配体门控离子通道7的配体(P2X7R)过表达白血病细胞诱导分化的巨噬细胞单钠尿酸盐(MSU)晶体诱导痛风炎症反应过程中NOD样受体家族3(NLRP3)蛋白、IL-1β、TNF-α表达情况。方法取人单核细胞白血病细胞系THP-1,并随机分为过表达组、空白组、模型组、对照组;过表达组和空白组分别转染P2X7R过表达质粒、空白载体质粒,转染5 d,将过表达组、空白组、模型组THP-1细胞用100 ng/mL的PMA刺激3 h后分化为巨噬细胞,另将MSU晶体用氢氧化钠溶解配制成浓度为100μg/mL的MSU乳糜状悬液加入培养液中孵育6 h;对照组正常培养。分别采用RT-PCR法和Western blot法测算巨噬细胞P2X7R mRNA、蛋白,ELISA法检测巨噬细胞上清液IL-1β、TNF-α,Western blot法测算巨噬细胞NOD样受体家族3(NLRP3)蛋白。结果与对照组比较,过表达组、空白组、模型组P2X7R mRNA和蛋白相对表达量升高,细胞上清液IL-1β、TNF-α水平升高,细胞NLRP3蛋白相对表达量升高(P均<0.05);与模型组、空白组比较,过表达组P2X7R mRNA、蛋白相对表达量升高,细胞上清液IL-1β、TNF-α水平升高,细胞NLRP3蛋白相对表达量升高(P均<0.05)。结论P2X7R过表达白血病细胞诱导分化的巨噬细胞MSU晶体诱导痛风炎症反应过程中IL-1β、TNF-α、NLRP3表达增加,IL-1β、TNF-α水平升高可能通过激活NLRP3蛋白来实现。

原子层沉积Al_(2)O_(3)对尖晶石LiNi_(0.5)Mn_(1.5)O_(4)正极材料的影响机理

为提升尖晶石相LiNi_(0.5)Mn_(1.5)O_(4)正极材料在深度荷电状态下的界面稳定性,采用原子层沉积法在单晶LiNi_(0.5)Mn_(1.5)O_(4)正极材料表面可控沉积了纳米级Al_(2)O_(3)层。改性后的LiNi_(0.5)Mn_(1.5)O_(4)正极材料表现出优异的长循环耐腐蚀性能(1C电流密度下循环500次的容量保持率高达94.7%)。进一步的表界面解析结果表明:原子层沉积技术构建的纳米级Al_(2)O_(3)包覆层能够明显抑制材料本体与电解液的腐蚀反应,降低过渡金属离子的不可逆溶解与析出;另外,基于HF表面刻蚀产生的AlF_(3)具有增强的耐刻蚀性能,可显著提升LiNi_(0.5)Mn_(1.5)O_(4)正极材料在长循环及高电压下的服役性能。

Ti_(3)C_(2)T_(x)超薄纳米片高效率去除废水中重金属的研究

通过刻蚀剥离法制备了Ti_(3)C_(2)T_(x)超薄纳米片,探究了其对废水中重金属离子的吸附特性。通过SEM、XRD、AFM、FT-IR、Raman对Ti_(3)C_(2)T_(x)超薄纳米片的形貌和结构进行了表征,通过ICP-MS对处理前后水体中重金属离子的含量进行了测试。结果表明剥离的Ti_(3)C_(2)T_(x)超薄纳米片表面含有结构缺陷和羟基,当水体中Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)初始浓度为50 mg/L时,47.5 mg Ti_(3)C_(2)T_(x)超薄纳米片对其的去除效率高达90%以上,尤其是对Pb(Ⅱ)的去除效率达到了98.81%,吸附性能远高于大孔树脂、硅藻土和活性炭等常见吸附试剂。在Na(Ⅰ)、Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)4种离子共存溶液中,Ti_(3)C_(2)T_(x)超薄纳米片对于Pb(Ⅱ)和Cr(Ⅵ)的去除依然可以达到92%以上。通过动力学和吸附等温拟合,Ti_(3)C_(2)T_(x)纳米片对Pb(Ⅱ)的吸附符合拟二级动力学模型和Langmuir等温模型,对Pb(Ⅱ)的最大吸附量和最低检出限分别为81.7 mg/g和0.0094 mg/L。Ti_(3)C_(2)T_(x)超薄纳米片对重金属离子的吸附特性在化学工业、食品加工的废水处理中具有良好的应用前景。

封装包覆结构多孔Fe_(3)O_(4)长循环锂电池负极材料

本文通过封装与包覆结构共同作用抑制多级孔Fe_(3)O_(4)在循环过程中的体积膨胀,提高Fe_(3)O_(4)电极材料的电化学性能。通过采用硬模板法将葡萄糖和尿素作为造孔剂合成具有多级孔结构的Fe_(3)O_(4)材料,再利用醛脂包覆系统在多级孔Fe_(3)O_(4)上均匀的包覆一层碳材料,随后使用氢化工程对体积膨胀率仅为~4%的TiO_(2)进行氢化处理并提高TiO_(2)的导电率,将氢化TiO_(2)作为封装材料对碳包覆多级孔Fe_(3)O_(4)进行封装处理,制备出具有三维网络传输结构的H-TiO_(2)-C-Fe_(3)O_(4)电极材料。结果表明,封装与包覆结构较好的缓解了H-TiO_(2)-C-Fe_(3)O_(4)电极材料在充放电过程中的体积膨胀,在0.2 A·g^(-1)的电流密度下循环500圈之后的放电比容量为599.61 mAh·g^(-1),以1 A·g^(-1)的电流密度循环700圈后的比容量为542.64 mAh·g^(-1),即使在6 A·g^(-1)的大电流密度下比容量也能够达到168.7 mAh·g^(-1),当电流返回0.2 A·g^(-1)循环100圈后的比容量为671.91 mAh·g^(-1),优异的倍率性能为H-TiO_(2)-C-Fe_(3)O_(4)样品在大电流储能设备上使用提供了可能性。

溶液燃烧法制备Nd^(3+)掺杂LaBO_(3)荧光粉

以La(NO_(3))_(3)·6H_(2)O、H_(3)BO_(3)为原料、C_(2)H_(5)NO_(2)为燃烧剂、Nd(NO_(3))_(3)·6H_(2)O为改性剂,通过溶液燃烧法合成Nd^(3+)掺杂LaBO_(3)荧光粉。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)以及荧光光谱(PL)对产物进行表征分析。结果表明,制备的粉体均为正交晶系硼酸镧,在煅烧温度875℃、Nd^(3+)掺杂量3%的优化条件下制备的硼酸镧荧光粉发光性能最好,且其在紫外光区和可见光区均表现出良好的光吸收性能,发蓝绿色光,可广泛应用于激光照明和LED照明等领域。

Bi/Bi_(3)Se_(4) nanoparticles embedded in hollow porous carbon nanorod:High rate capability material for potassium-ion batteries

Considering their superior theoretical capacity and low voltage plateau,bismuth(Bi)-based materials are being widely explored for application in potassium-ion batteries(PIBs).Unfortunately,pure Bi and Bibased compounds suffer from severe electrochemical polarization,agglomeration,and dramatic volume fluctuations.To develop an advanced bismuth-based anode material with high reactivity and durability,in this work,the pyrolysis of Bi-based metal-organic frameworks and in-situ selenization techniques have been successfully used to produce a Bi-based composite with high capacity and unique structure,in which Bi/Bi_(3)Se_(4)nanoparticles are encapsulated in carbon nanorods(Bi/Bi_(3)Se_(4)@CNR).Applied as the anode material of PIBs,the Bi/Bi_(3)Se_(4)@CNR displays fast potassium storage capability with 307.5 m A h g^(-1)at 20 A g^(-1)and durable cycle performance of 2000 cycles at 5 A g^(-1).Notably,the Bi/Bi_(3)Se_(4)@CNR also showed long cycle stability over 1600 cycles when working in a full cell system with potassium vanadate as the cathode material,which further demonstrates its promising potential in the field of PIBs.Additionally,the dual potassium storage mechanism of the Bi/Bi_(3)Se_(4)@CNR based on conversion and alloying reaction has also been revealed by in-situ X-ray diffraction.

HL-3装置上离子回旋波加热对中子产额的影响

离子回旋射频(Ion Cyclotron Range of Frequencies,ICRF)波加热是托卡马克装置上至关重要的辅助加热方式之一。托卡马克装置中国环流三号(HL-3,原名HL-2M)拟安装加热功率为6 MW的ICRF加热系统。本工作利用TRANSP程序,模拟并研究了ICRF加热的频率和功率对聚变中子产额以及快离子分布的影响。研究结果表明:ICRF的频率和功率对中子产额有显著影响,固定ICRF频率时,中子产额与加热功率成正比关系,而在固定ICRF加热功率的情况下,中子产额的增加幅度显著依赖ICRF的频率,在研究参数范围内,30 MHz的ICRF对中子产额的增加具有最显著的增强作用。快离子分布的模拟结果显示,在考虑ICRF加热后,中性束和ICRF的协同加热机制能够将快离子加热至最高1 MeV,有效地提高了中子产额。此外,基于中子相机诊断的概念对中子信号进行了仿真。结果表明,中子相机能够有效地测量到由ICRF加热导致的中子产额高低和分布剖面的变化,这为将来优化中子相机诊断系统设计和测量中子空间分布提供了一定的参考。

Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)正极材料的Ga_(2)O_(3)包覆改性及电化学性能

首先采用共沉淀方法制备富锂锰基正极材料Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)原始样品(P-LRMO),然后通过简单的湿化学法以及低温煅烧方法对其进行不同含量Ga_(2)O_(3)原位包覆。透射电子显微镜(TEM)以及X射线光电子能谱(XPS)结果表明在P-LRMO表面成功合成了Ga_(2)O_(3)包覆层。电化学测试结果表明:含有3%Ga_(2)O_(3)的改性材料G3-LRMO具有最优的电化学性能,其在0.1C倍率(电流密度为25 mA·g^(-1))下首圈充放电比容量可以达到270.1 mAh·g^(-1),在5C倍率下容量仍能保持127.4 mAh·g^(-1),优于未改性材料的90.7 mAh·g^(-1),表现出优异的倍率性能。G3-LRMO在1C倍率下循环200圈后仍有190.7 mAh·g^(-1)的容量,容量保持率由未改性前的72.9%提升至85.6%,证明Ga_(2)O_(3)包覆改性能有效提升富锂锰基材料的循环稳定性。并且,G3-LRMO在1C倍率下循环100圈后,电荷转移阻抗(Rct)为107.7Ω,远低于未改性材料的251.5Ω,表明Ga_(2)O_(3)包覆层能提高材料的电子传输速率。

锂离子电池负极材料ZnSnO_(3)/C复合物的制备与性能

锡基双金属氧化物作为锂离子电池负极材料因具有高的理论比容量、嵌脱锂电位适中、储量丰富、价格低廉、安全性高以及环保等优点,已经受到了广泛的关注.本研究采用一步原位水热法制备了碳包覆的ZnSnO_(3)复合材料(ZnSnO_(3)/C).利用扫描电子显微镜、透射电子显微镜、X射线衍射、拉曼光谱、X射线光电子能谱分析和恒流充放电测试等一系列表征测试方法对材料的微观形貌、物相组成、结构和电化学性能进行分析.电化学测试结果表明:当作为锂离子电池负极材料时,ZnSnO_(3)/C复合电极的储锂性能优于纯ZnSnO_(3)电极.在200 mA·g^(-1)电流密度下,ZnSnO_(3)/C复合电极经200次循环后可逆容量可达1274.9 mA·h·g^(-1),即使在大电流5000 mA·g^(-1)下经500次循环仍然提供663.2 mA·h·g^(-1)的放电比容量,同时也表现出卓越的倍率性能.优异的储量性能归因于ZnSnO_(3)/C复合材料中具有高电导率的C不仅提高了整个电极的导电性,有利于电子的传输,而且增大了电解液与活性材料之间的接触面积,缩短了锂离子的扩散距离;同时碳包覆层可有效缓冲ZnSnO_(3)在嵌脱锂过程中由于体积变化产生的应力,也能在一定程度上抑制ZnSnO_(3)在循环过程中的团聚.