储能科学与技术, 2022, 11(6): 1883-1891 doi: 10.19799/j.cnki.2095-4239.2022.0198

化工与储能专刊

氮掺杂碳包覆Na3V2PO42F3 钠离子电池正极材料的制备与性能

赵易飞,1, 杨振东1, 李凤1, 谢召军1, 周震,1,2

1.南开大学材料科学与工程学院,天津 300350

2.郑州大学化工学院,河南 郑州 450001

Nitrogen-doped carbon-coated Na3V2PO42F3 cathode materials for sodium-ion batteriesPreparation and electrochemical performance

ZHAO Yifei,1, YANG Zhendong1, LI Feng1, XIE Zhaojun1, ZHOU Zhen,1,2

1.School of Materials Science and Engineering, Nankai University, Tianjin 300350, China

2.School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China

通讯作者: 周震,教授,研究方向为新能源材料与器件,E-mail:zhouzhen@nankai.edu.cn

收稿日期: 2022-04-11   修回日期: 2022-04-25  

基金资助: 国家自然科学基金项目.  21773126

Received: 2022-04-11   Revised: 2022-04-25  

作者简介 About authors

赵易飞(1993—),男,硕士,研究方向为钠离子电池正极材料,E-mail:595866390@qq.com; E-mail:595866390@qq.com

摘要

锂储量的有限性和不断攀升的锂资源价格限制了锂离子电池在大规模能源存储领域的应用发展,亟需发展可替代锂离子电池的低成本储能技术。在诸多新型二次电池储能体系中,钠离子电池由于钠资源丰富及与锂离子电池相似的储能机制受到了广泛关注。在钠离子电池正极材料中,钠超离子导体材料Na3V2(PO4)2F3(NVPF)不仅具有高的工作电压和放电容量,还表现出良好的热稳定性和较小的体积效应,因而具有广阔的应用前景。本工作采用低温水热反应和后续煅烧法制备NVPF,通过在水热过程中添加尿素和柠檬酸制备了氮掺杂碳包覆NVPF的复合材料(NVPF@C-N)。氮元素掺杂改善了碳包覆层的孔道结构和电导率,NVPF@C-N复合材料作为钠离子电池正极材料表现出高的可逆容量以及优异的倍率性能,在1 C下的初始放电比容量为121 mAh/g,10 C下的放电比容量为110 mAh/g,甚至在90 C的高电流密度下放电比容量仍具有66 mAh/g。此外,NVPF@C-N正极材料展示了高的循环稳定性,在1 C下循环200次后的充放电平台能够得到充分保持,且放电比容量仍高达111 mAh/g;特别地,NVPF@C-N在10 C下循环1000次后的容量保持率高达87%,在6000次循环后的容量保持率为54%。

关键词: 钠离子电池 ; Na3V2(PO4)2F3 ; 碳包覆 ; 氮掺杂 ; 高倍率

Abstract

The limited lithium reserves and the increasing cost of lithium sources have hampered extensive applications of lithium-ion batteries to large-scale electric energy storage. It is significantly urgent to develop alternative low-cost electric energy storage devices, during which rechargeable sodium-ion batteries (SIBs) have attracted extensive attention due to abundant sodium resources and similar electrochemical properties to lithium-ion batteries. Na3V2(PO4)2F3 (NVPF) is considered as one of the most promising candidates, owing to the merits of super high ionic conductivity, high theoretical specific capacity, good thermal stability and small volume effect. In this work, through hydrothermal process and post calcination, nitrogen-doped carbon-coated NVPF (NVPF@C-N) composites were obtained by adding urea and citric acid during the hydrothermal process. Particularly, nitrogen doping could substantially enhance the pore structure and electrical conductivity of the carbon layer. When used as the SIB cathode, NVPF@C-N exhibited high reversible capacity and excellent rate capability. Under 1 C and 10 C rates, the NVPF@C-N cathode delivered initial discharge capacity of 121 mAh/g and 110 mAh/g, respectively. Even at the rate of 90 C, 66 mAh/g can be obtained. For the cycling stability of NVPF@C-N, the voltage plateau still could be well maintained even after 200 cycles at the rate of 1 C, and the electrode still retained a capacity of 111 mAh/g. Particularly, a retention of 87% was obtained after 1000 cycles at the rate of 10 C, and a retention of 54% was still maintained even after 6000 cycles.

Keywords: sodium ion batteries ; Na3V2(PO4)2F3 ; carbon coating ; nitrogen doping ; high-rate performance

PDF (3659KB) 元数据 多维度评价 相关文章 导出 EndNote| Ris| Bibtex  收藏本文

本文引用格式

赵易飞, 杨振东, 李凤, 谢召军, 周震. 氮掺杂碳包覆Na3V2PO42F3 钠离子电池正极材料的制备与性能[J]. 储能科学与技术, 2022, 11(6): 1883-1891

ZHAO Yifei. Nitrogen-doped carbon-coated Na3V2PO42F3 cathode materials for sodium-ion batteriesPreparation and electrochemical performance[J]. Energy Storage Science and Technology, 2022, 11(6): 1883-1891

随着传统化石类燃料逐渐短缺枯竭以及过度开采使用所带来的环境问题日益突出,新能源产业正在不断崛起,受到人们越来越多的关注。储能系统能够弥补太阳能、风能、潮汐能等新能源在空间和时间上的不均匀性[1-2],使新能源顺利应用于工业生产和日常生活之中。电池储能技术由于具有低成本、便于存储与转运、无污染、高能量转化效率以及可观的使用寿命等特性,得到了广泛的应用与发展。二次电池的成功研发,特别是20世纪90年代锂离子电池的商业化发展,促进了信息、通信和电子技术等产业的飞速进步[3-4]。锂离子电池具有高的能量密度、长的循环寿命、可快速充电以及无记忆效应等优势,目前在便携式电子设备和电动工具等领域占据主导地位,并逐步拓展到了储能和新能源汽车领域[5-6]。然而,锂资源在地壳当中存储量仅占地表丰度的0.006%,在地球上的分布也极不均匀,主要集中于南美洲,而且某些地理位置开采难度巨大[7-8]。随着二次电池将来大规模的应用发展,锂的原材料价格势必成为限制其自身发展的关键因素。

相比于锂元素,钠资源储量非常丰富,在地壳中的含量为2.64%,约是锂元素含量的440倍,价格低廉且资源分布广泛易于开采[9-10]。此外,由于钠不与铝发生合金化反应,可用较廉价的铝箔取代铜箔作为负极集流体应用于钠离子电池,能够进一步降低电池成本,以弥补由于钠原子质量较大而导致较低能量密度的缺陷[11]。钠与锂为同一主族元素,具有相似的物理与化学性质,钠离子电池被认为是最具潜力的下一代二次电池储能体系之一,在智能电网、移动物联网、大规模储能电站和电动车领域有着广阔的应用前景,成为近年来储能领域研究与开发的热点[12]

在钠离子电池正极材料的研究中,钠超离子导体(NASICON)材料因具有稳定的三维结构以及可保证Na+的快速插入与脱出能力受到研究者的广泛青睐[13-15]。在这类电极材料中,Na3V2(PO4)2F3(NVPF)由于PO43-聚阴离子的诱导效应和强的V—F离子键,表现出高的工作电压(3.95 V vs. Na/Na+)和高的理论比容量(128 mAh/g),其理论能量密度高达500 Wh/kg[16-18]。然而,与其他聚阴离子型电极材料一样,由于V原子被PO43-四面体隔离,NVPF的电子导电率极低(10-12 S/cm)[19-20]。未经修饰的NVPF材料即使在低电流密度下仍然难以获得高比容量,阻碍了该材料的实际应用。为解决这一困境,合理的微/纳结构设计[21-22]以及构筑碳基复合物[23-26]是常用增强电子导电性和电化学性能的有效策略。值得注意的是,由于大的比表面积和高的表面能,NVPF纳米颗粒在复合物中常呈现不均匀分布和严重团聚的现象,导致差的电解液浸润和加剧的界面阻抗,限制了高倍率性能。因此,发展简单有效的NVPF复合正极材料制备方法能够推动高性能钠离子电池的商业化应用。

本工作主要通过对NVPF进行表面氮掺杂碳包覆来改善材料电子和离子电导率,以获得高可逆容量以及出色倍率性能的钠离子电池正极材料。选择尿素和柠檬酸为氮源和碳源,在低温水热反应中可实现对NVPF前体的均匀包覆,经后续高温煅烧制备了氮掺杂碳包覆NVPF复合材料(NVPF@C-N),并通过半电池组装测试验证了复合材料优异的电化学性能,该研究有助于高性能钠离子电池正极材料的设计制备。

1 实验材料和方法

1.1 材料制备

采用低温水热反应和后续煅烧制备NVPF材料,通过在水热过程中添加尿素和柠檬酸制备了NVPF@C-N复合材料。具体过程如下:首先,将原料NaF、NH4H2PO4和NH4VO3以3∶2∶2的摩尔比溶解在去离子水中,同时将柠檬酸用作螯合剂和碳源,将尿素作为氮源添加到上述反应溶液中。其次,混合溶液在70 ℃下连续搅拌反应0.5 h,后转移至内衬为聚四氟乙烯的不锈钢高压反应釜中,并将反应釜置于110 ℃的烘箱中加热7 h。然后,将水热产物于冰箱中冷冻24 h,后用冷冻干燥机干燥,并将所得样品在研钵中研磨1 h至粉状。最后,将所得前体在氩气气氛下于300 ℃烧结4 h,之后于650 ℃烧结8 h,得到NVPF@C-N复合材料。对照组材料的制备:除在水热前体中不添加尿素或不添加柠檬酸和尿素外,按照与NVPF@C-N相同步骤制备了NVPF@C样品和NVPF样品。

1.2 材料表征

采用日本理学MiniFlex-600型X射线衍射仪(XRD)分析所制备样品的物相组成,测试条件为:铜靶,射线波长0.1541 nm,扫描范围为2°~80°,扫速为10(°)/min。采用英国雷尼绍In Via型拉曼光谱仪(Raman)测定样品分子中的特征化学结构。采用日本ULVAC-PHI型号为PHI 5000 Versa Probe的X射线光电子能谱仪(XPS)分析探测样品表面的元素构成。采用日本JEOL型号为JSM-7500F扫描电子显微镜(SEM)分析材料的微观形貌和结构。采用日本JEOL型号为JEM-3010透射电子显微镜(TEM)获得样品高放大倍数下的微观形貌和晶格信息。采用美国康塔型号为NOVA 2000e比表面分析仪分析样品的比表面积和孔径分布(BET)。

1.3 电极制备和电池组装测试

将制备的各种NVPF正极材料、导电碳(科琴黑)和黏结剂(羧甲基纤维素钠和聚丙烯酸钠)按7∶2∶1的质量比加入小坩埚中,加入适量的去离子水进行混合匀浆,将电极浆料均匀涂覆在铝箔上,待浆料表层水分挥发后,在110 ℃下真空干燥10 h,并用压片机裁剪出直径为12 mm的圆形极片。在水氧含量均小于0.1 mg/m3的充满氩气的手套箱中组装电池,选用金属钠片为负极,玻璃纤维为隔膜,1 mol/L NaClO4的碳酸亚乙酯(EC)和碳酸亚丙酯(PC)(体积比1∶1)及5%氟代碳酸乙烯酯(FEC)溶液为电解液,使用型号为CR 2025的扣式电池模具进行组装,组装好的电池静置10 h后进行电化学性能测试。恒电流充放电测试采用武汉蓝电型号为CT2001ACT2001A的LAND测试系统,循环伏安测试(CV)采用上海辰华CHI-600型电化学工作站,电压范围为2.3~4.5 V (vs. Na/Na+)。交流阻抗测试(EIS)测试工作站为德国Zahner-Elektrik IM6e,频率范围为10 mHz~100 kHz,测试振幅为5 mV。

2 结果与讨论

2.1 材料结构特征

图1为所制备3种材料NVPF@C-N、NCPF@C及NVPF的XRD谱图。可以看出,3种样品的主要X射线衍射峰包括其峰位置和强度十分接近,且都符合NASICON结构的NVPF相(JCPDS,编号04-012-2207)。这表明在采用水热反应和后续煅烧方法制备NVPF过程中,添加尿素和柠檬酸并不影响最终产物NVPF的晶体结构。

图1

图1   NVPF@CNVPF@C-NNVPFXRD谱图

Fig. 1   XRD patterns of NVPF@C-N, NVPF@C and NVPF


进一步通过Raman光谱和XPS对NVPF@C-N复合材料的碳包覆层进行了深入研究。如图2(a)所示,Raman光谱中1354 cm-1和1594 cm-1两处峰为类石墨的特征吸收,分别对应碳层的D带和G带。对于NVPF@C-N材料,D带和G带峰强度比值ID/IG为0.98,而NVPF@C材料中的ID/IG为0.94,表明氮元素的加入会让NVPF包覆碳层生成更多的缺陷[27]。如图2(b)所示,NVPF@C-N的比表面积为319.62 m2/g,平均孔径约为8 nm,而未进行包覆的NVPF的比表面积为152.18 m2/g,平均孔径约为5 nm,说明氮杂碳包覆增加了材料的比表面积和孔隙率,有利于钠离子的传输。为了进一步确定氮元素在材料中的存在形式,对NVPF@C-N样品进行了XPS测试。从NVPF@C-N的高分辨XPS图中可以看出,其C1s谱可以分为4个峰[图2(c)]。在电子结合能为284.5 eV处的尖锐峰对应于具有C=C键的sp2-C,而在电子结合能为285.3 eV、286.2 eV和288.9 eV处的3个强度较弱的峰分别对应于C—C键、C—N键和O—C=O键[28-31]。C—N键的存在表明氮元素掺入了碳层中。如图2(d)所示,高分辨率N1s谱中显示在398.3 eV和399.5 eV处有两个峰,分别对应于吡啶氮和吡咯氮[32]。碳层中吡啶N和吡咯N的引入可以提供大量缺陷和钠离子活性位点,进而增强离子电导率,同时氮掺杂还可以提高碳包覆层的电子电导率[33-34]

图2

图2   (a) NVPF@C-NNVPF@C材料的Raman光谱;(b) NVPF@C-NNVPF材料的BET曲线及孔径分布;NVPF@C-N复合材料的XPS精细谱(c) C元素,(d) N元素

Fig. 2   (a) Raman spectra of NVPF@C-N and NVPF@C; (b) BET analysis and pore size distribution of NVPF@C-N and NVPF; The high-resolution XPS spectra of the NVPF@C-N material: (c) C, (d) N


图3展示了NVPF和NVPF@C-N样品的形貌、颗粒尺寸以及元素分布。从图3(a)、(b)中可以看出,NVPF和NVPF@C-N样品均由微颗粒聚集构成。相比于NVPF,NVPF@C-N样品颗粒更加圆滑,颗粒间由碳材料紧密连接,样品中的三维孔道结构说明烧结过程中生成的碳质材料缓冲了NVPF晶粒生长产生的应力。由图3(c)、(d)高分辨透射电镜图像可以看出,NVPF@C-N材料中NVPF晶体颗粒的表面覆盖有碳包覆层,且碳层与NVPF颗粒紧密相连。图3(d)中存在的晶格条纹显示颗粒具有明显的晶体结构,其晶格条纹间隔为0.411 nm,对应于NVPF晶体结构的(112)晶面。图3(e)~(g)为NVPF@C-N复合材料的元素分布图,可以看出C和N元素分布均匀,表明选用尿素作为氮源进行掺杂经济有效。

图3

图3   (a) NVPF(b) NVPF@C-N扫描电镜图;(c)(d) NVPF@C-N透射电镜图;(e)(g) NVPF@C-N元素分布图

Fig. 3   (a) SEM images of NVPF and (b) NVPF@C-N; (c) TEM image of NVPF@C-N; (d) HRTEM image of NVPF@C-N; (e)-(g) Elemental mapping images of NVPF@C-N


2.2 电化学性能

为了研究NVPF@C-N作为正极材料的储钠性能,对其与金属钠组装的扣式半电池进行了相关的电化学测试,电化学窗口为2.3~4.5 V(vs. Na/Na+),测定结果如图4所示。从图4(a)中的CV曲线可以看出,NVPF@C-N电极具有2对可逆氧化还原峰和1对准可逆氧化还原峰,分别对应着V3+/V4+的氧化以及还原,伴随着单元结构中2个Na+的脱出与嵌入[35]。CV测试中的4个充放电循环基本重合,3对氧化还原峰的极化差值分别为0.13 V、0.15 V和0.15 V,说明NVPF@C-N电极具有高度的电化学可逆性及良好的电子和离子传输动力学性能。图4(b)为3种NVPF正极材料的恒电流充放电测试曲线,在1 C倍率下3种NVPF正极均存在2个独立的放电平台,约为4.1 V和3.6 V,对应着四价钒还原为三价钒,与CV测试中NVPF@C-N电极电化学行为相一致。值得注意的是,NVPF@C-N电极1 C电流密度下的首周放电比容量为121 mAh/g,高于其他两种正极材料,说明NVPF@C-N电极具有较快的反应动力学过程。

图4

图4   NVPF@C-N组装的钠离子半电池的电化学性能。(a) 扫速为0.1 mV/sCV曲线;(b) NVPF, NVPF@CNVPF@C-N1 C倍率下的首周充放电曲线;(c) NVPF, NVPF@CNVPF@C-N1 C90 C倍率下的放电比容量图;(d) 与其他NVPF正极材料电化学性能比较

Fig. 4   Electrochemical performance of NVPF@C-N cathode in sodium-ion half-cell. (a) The first four CV curves at a scan rate of 0.1 mV/s between 2.3 V and 4.5 V; (b) The first charge/discharge profiles of NVPF, NVPF@C and NVPF@C-N at 1 C; (c) The rate capacity from 1 C to 90 C of NVPF, NVPF@C and NVPF@C-N; (d) The comparison of rate performance for NVPF cathodes


为了进一步验证氮掺杂碳包覆层对NVPF材料电子和离子电导率的提升效果,对NVPF@C-N、NVPF@C和NVPF 3种材料组装的半电池进行了倍率性能测试,结果如图4(c)所示。NVPF@C与NVPF相比较而言,在低电流密度下(<15 C)前者具有更高的放电比容量,在高电流密度下两者的放电比容量相当,说明碳包覆层可以起到提升电子导电性的作用,但其会影响钠离子的快速传输过程。与之相比,NVPF@C-N在高倍率性能下依然具有很高的放电比容量,且从低倍率(1 C)到高倍率(90 C)其放电比容量相较于NVPF均有极大地提升。当放电电流密度在30 C时,NVPF@C-N放电比容量仍可达到100 mAh/g,是其在1 C电流密度下放电比容量的83%。即使在90 C的高电流密度下,NVPF@C-N的放电比容量仍可达到66 mAh/g。倍率性能测试结果充分表明氮原子的掺入改善了碳包覆层的离子和电子传输能力,氮杂碳包覆层大幅提升NVPF正极材料的倍率性能。此外,进一步对NVPF@C-N材料与其他同类型正极材料的倍率性能进行了对比,如图4(d)所示,NVPF@C-N复合材料所组装电池在不同的倍率下所能释放的放电比容量优于其他同类材料[36-41],由此说明通过对NVPF进行表面氮掺杂碳包覆可以获得高倍率性能的钠离子电池正极材料。

图5(a)所示,我们还用所测得的电化学数据绘制出所组装半电池能量密度对应于功率密度的Ragone图。从图中曲线可以看出,在释放相同功率密度时NVPF@C-N所具备的能量密度要比NVPF@C高很多。当能量密度为210 Wh/kg时,NVPF@C-N复合材料可以达到3.5×104 W/kg以上的功率密度,这归因于正极材料的倍率性能得到了大幅提升。优异的电化学性能使其成为具有最高功率密度和能量密度的钠离子电池正极材料之一[42]

图5

图5   (a) NVPF@C-NNVPF@C电池的拟合Ragone图;(b) NVPF@C-N电极1 C倍率下选定循环周数下的充放电曲线;(c) NVPF@C-N电极在10 C倍率下的循环性能

Fig. 5   (a) Corresponding Ragone plots of NVPF@C-N and NVPF@C; (b) The charge/discharge profiles of the selected cycles at 1 C for NVPF@C-N cathode; (c) The long cycling performance of NVPF@C-N at 10 C


电极材料的循环稳定性对于电池体系同样至关重要。首先研究了NVPF@C-N材料在1 C电流密度下的循环性能,结果如图5(b)所示。可以看出,NVPF@C-N在循环过程中的充放电曲线仍具有明显的电压平台,未发生显著退化。100次循环后的放电比容量为115 mAh/g,为初始放电比容量的95%,而200次循环后的放电比容量仍具有111 mAh/g,NVPF@C-N初步表现出了优异的循环稳定性能。之后,对NVPF@C-N组装的电池在10 C电流密度下进行了长循环性能测试,由图5(c)可以看出,初始放电比容量为110 mAh/g,在1000次循环后电池容量保持率为87%,在1600次循环后电池容量保持率为80%,在6000次循环后的容量保持率仍有54%。除了第1周循环外,电池在6000次循环中的库仑效率基本保持在100%。NVPF@C-N材料较高的循环稳定性能主要得益于氮杂碳包覆层,既能够保证电极材料与电解液的有效接触并减少活性材料的腐蚀,又能够稳定NVPF在Na+快速插入与脱出中所引起的结构应力变化,保证了NVPF活性材料的有效电接触。尽管如此,高倍率长循环过程中钠离子的反复脱嵌仍会削弱NVPF与碳包覆层电接触,而降低的材料利用率和变差的电化学反应动力学导致了充放电容量逐渐衰减 [41,43-46]

为了探究氮原子掺杂对碳包覆导电性能的影响,对循环5次后的NVPF@C-N和NVPF@C电极进行了EIS测试,结果如图6所示。可以看出,奈奎斯特曲线均包括高频区的一个半圆和低频区的一条直线,其中高频区单个半圆对应于电荷转移电阻(Rct),低频区中的斜线则对应于体相中钠离子扩散过程的Warburg阻抗[47]。等效电路图中的电阻器Rs代表内部电阻,包括颗粒与颗粒间电阻、电解质电阻以及在高频截距处电极与集电器之间的电阻[48],并基于电化学阻抗数据,利用式(1)~式(3)计算得到了NVPF@C-N和NVPF@C复合材料的Na+离子扩散系数DNa+[49]

图6

图6   NVPF@C-NNVPF@C正极材料的阻抗图

Fig. 6   Nyquist plots for the NVPF@C-N and NVPF@C electrodes


ω=2πf
Z′=Rs+Rct+σω-1/2
DNa+=0.5R2T2/A2n2F4C2σ2

式中,ω为低频区的角速度;f为低频区的频率;R为热力学常数;T为绝对温度;A为电极面积;n为每摩尔材料转移电子数;F为法拉第常数;C为钠离子浓度。EIS等效电路拟合数据列于表1中。可以看出,与NVPF@C相比,NVPF@C-N电极的Rs(5.4 Ω)和Rct(220.4 Ω)数值更小,DNa+较高,表明氮掺杂提升了碳包覆层的钠离子的嵌入和脱出,使得NVPF@C-N电极具有优异的倍率性能。

表1   NVPF@C-NNVPF@C复合材料的拟合 RsRct 以及 DNa+ 数据

Table 1  Rct, Rs and DNa+ values from EIS data of NVPF@C-N and NVPF@C

样品RctRsDNa+
NVPF@C-N220.45.47.75×10-10
NVPF@C541.232.83.22×10-10

新窗口打开| 下载CSV


3 结论

在使用低温水热反应和后续煅烧法制备钠超离子导体NVPF过程中,通过在水热反应中添加尿素和柠檬酸能够制备出均匀氮掺杂碳包覆的复合材料NVPF@C-N。氮元素掺杂可以改善碳包覆层的孔道结构和电导率,确保了NVPF@C-N复合材料的电子和离子的传输性能。NVPF@C-N作为钠离子电池正极材料表现出高的可逆容量和优异的倍率性能,在1 C下的初始放电比容量为121 mAh/g,10 C下的放电比容量为110 mAh/g,甚至在90 C的高电流密度下放电比容量仍达66 mAh/g。在10 C下循环1000次后的容量保持率高达87%,循环6000次后的容量保持率仍为54%。相关研究对于开发高性能钠离子电池正极材料具有借鉴意义。

参考文献

ARMAND M, TARASCON J M. Building better batteries[J]. Nature, 2008, 451(7179): 652-657.

[本文引用: 1]

YANG Z G, ZHANG J L, KINTNER-MEYER M C W, et al. Electrochemical energy storage for green grid[J]. Chemical Reviews, 2011, 111(5): 3577-3613.

[本文引用: 1]

DUNN B, KAMATH H, TARASCON J M. Electrical energy storage for the grid: A battery of choices[J]. Science, 2011, 334(6058): 928-935.

[本文引用: 1]

HU M, PANG X L, ZHOU Z. Recent progress in high-voltage lithium ion batteries[J]. Journal of Power Sources, 2013, 237: 229-242.

[本文引用: 1]

WANG P F, YOU Y, YIN Y X, et al. Layered oxide cathodes for sodium-ion batteries: Phase transition, air stability, and performance[J]. Advanced Energy Materials, 2018, 8(8): doi:10.1002/aenm.201701912.

[本文引用: 1]

ZHANG X, YANG Y A, ZHOU Z. Towards practical lithium-metal anodes[J]. Chemical Society Reviews, 2020, 49(10): 3040-3071.

[本文引用: 1]

ETACHERI V, MAROM R, ELAZARI R, et al. Challenges in the development of advanced Li-ion batteries: A review[J]. Energy & Environmental Science, 2011, 4(9): 3243-3262.

[本文引用: 1]

ETACHERI V, MAROM R, ELAZARI R, et al. Challenges in the development of advanced Li-ion batteries: A review[J]. Energy & Environmental Science, 2011, 4(9): 3243.

[本文引用: 1]

XIAO Y, LEE S H, SUN Y K. The application of metal sulfides in sodium ion batteries[J]. Advanced Energy Materials, 2017, 7(3): doi:10.1002/aenm.201601329.

[本文引用: 1]

YANG M, ZHONG Y R, BAO J, et al. Achieving battery-level energy density by constructing aqueous carbonaceous supercapacitors with hierarchical porous N-rich carbon materials[J]. Journal of Materials Chemistry A, 2015, 3(21): 11387-11394.

[本文引用: 1]

DE LA LLAVE E, BORGEL V, PARK K J, et al. Comparison between Na-ion and Li-ion cells: Understanding the critical role of the cathodes stability and the anodes pretreatment on the cells behavior[J]. ACS Applied Materials & Interfaces, 2016, 8(3): 1867-1875.

[本文引用: 1]

HU Z, ZHU Z Q, CHENG F Y, et al. Pyrite FeS2 for high-rate and long-life rechargeable sodium batteries[J]. Energy & Environmental Science, 2015, 8(4): 1309-1316.

[本文引用: 1]

KIM S W, SEO D H, MA X H, et al. Electrode materials for rechargeable sodium-ion batteries: Potential alternatives to current lithium-ion batteries[J]. Advanced Energy Materials, 2012, 2(7): 710-721.

[本文引用: 1]

SONG W X, JI X B, WU Z P, et al. First exploration of Na-ion migration pathways in the NASICON structure Na3V2(PO4)3[J]. Journal of Materials Chemistry A, 2014, 2(15): 5358.

[本文引用: 1]

WARNER T E, MILIUS W, MAIER J. New copper phosphates with the NASICON or alluaudite-type structures as ionic or mixed conductors[J]. Solid State Ionics, 1994, 74(3/4): 119-123.

GUO J Z, WANG P F, WU X L, et al. High-energy/power and low-temperature cathode for sodium-ion batteries: In situ XRD study and superior full-cell performance[J]. Advanced Materials, 2017, 29(33). doi:10.1002.adma.201701968.

[本文引用: 1]

LIU Q, WANG D X, YANG X, et al. Carbon-coated Na3V2(PO4)2F3 nanoparticles embedded in a mesoporous carbon matrix as a potential cathode material for sodium-ion batteries with superior rate capability and long-term cycle life[J]. Journal of Materials Chemistry A, 2015, 3(43): 21478-21485.

[本文引用: 1]

BIANCHINI M, FAUTH F, BRISSET N, et al. Comprehensive investigation of the Na3V2(PO4)2F3-NaV2(PO4)2F3 system by operando high resolution synchrotron X-ray diffraction[J]. Chemistry of Materials, 2015, 27(8): 3009-3020.

SERRAS P, PALOMARES V, ALONSO J, et al. Electrochemical Na extraction/insertion of Na3V2O2 x(PO4)2F3-2 x[J]. Chemistry of Materials, 2013, 25(24): 4917-4925.

[本文引用: 1]

YI H M, LING M X, XU W B, et al. VSC-doping and VSU-doping of Na3V2- xTix(PO4)2F3 compounds for sodium ion battery cathodes: Analysis of electrochemical performance and kinetic properties[J]. Nano Energy, 2018, 47: 340-352.

[本文引用: 1]

XIANG X D, LU Q Q, HAN M, et al. Superior high-rate capability of Na3(VO0.5)2(PO4)2F2 nanoparticles embedded in porous graphene through the pseudocapacitive effect[J]. Chemical Communications, 2016, 52(18): 3653-3656.

[本文引用: 1]

JIN H Y, DONG J, UCHAKER E, et al. Three dimensional architecture of carbon wrapped multilayer Na3V2O2(PO4)2F nanocubes embedded in graphene for improved sodium ion batteries[J]. Journal of Materials Chemistry A, 2015, 3(34): 17563-17568.

[本文引用: 1]

WEI T Y, YANG G Z, WANG C X. Bottom-up assembly of strongly-coupled Na3V2(PO4)3/C into hierarchically porous hollow nanospheres for high-rate and-stable Na-ion storage[J]. Nano Energy, 2017, 39: 363-370.

[本文引用: 1]

KUMAR P R, JUNG Y H, KIM D K. Influence of carbon polymorphism towards improved sodium storage properties of Na3V2O2 x(PO4)2F3-2 x[J]. Journal of Solid State Electrochemistry, 2017, 21(1): 223-232.

[本文引用: 1]

PARK S, SONG J J, KIM S, et al. Phase-pure Na3V2(PO4)2F3 embedded in carbon matrix through a facile polyol synthesis as a potential cathode for high performance sodium-ion batteries[J]. Nano Research, 2019, 12(4): 911-917.

KUMAR P R, JUNG Y H, WANG J E, et al. Na3V2O2(PO4)2F-MWCNT nanocomposites as a stable and high rate cathode for aqueous and non-aqueous sodium-ion batteries[J]. Journal of Power Sources, 2016, 324: 421-427.

ZHU C B, WU C, CHEN C C, et al. A high power-high energy Na3V2(PO4)2F3 sodium cathode: Investigation of transport parameters, rational design and realization[J]. Chemistry of Materials, 2017, 29(12): 5207-5215.

[本文引用: 1]

WANG C, SHEN W, LIU H M. Nitrogen-doped carbon coated Li3V2(PO4)3 derived from a facile in situ fabrication strategy with ultrahigh-rate stable performance for lithium-ion storage[J]. New Journal of Chemistry, 2014, 38(1): 430-436.

[本文引用: 1]

SHEN W, WANG C, XU Q J, et al. Nitrogen-doping-induced defects of a carbon coating layer facilitate Na-storage in electrode materials[J]. Advanced Energy Materials, 2015, 5(1): doi:10.1002/aenm.201400982.

[本文引用: 1]

NIE P, ZHU Y Y, SHEN L F. From biomolecule to Na3V2(PO4)3/nitrogen-decorated carbon hybrids: Highly reversible cathodes for sodium-ion batteries[J]. Journal of Materials Chemistry A, 2014, 2(43): 18606-18612.

ZHANG C L, LI H S, PING N, et al. Facile synthesis of nitrogen-doped carbon derived from polydopamine-coated Li3V2(PO4)3 as cathode material for lithium-ion batteries[J]. RSC Advances, 2014, 4(73): 38791-38796.

WANG C, WANG F X, LIU Z C, et al. N-doped carbon hollow microspheres for metal-free quasi-solid-state full sodium-ion capacitors[J]. Nano Energy, 2017, 41: 674-680.

[本文引用: 1]

ZHANG L L, MA D, LI T, et al. Polydopamine-derived nitrogen-doped carbon-covered Na3V2(PO4)2F3 cathode material for high-performance Na-ion batteries[J]. ACS Applied Materials & Interfaces, 2018, 10(43): 36851-36859.

[本文引用: 1]

SHIN W H, JEONG H M, KIM B G, et al. Nitrogen-doped multiwall carbon nanotubes for lithium storage with extremely high capacity[J]. Nano Letters, 2012, 12(5): 2283-2288.

[本文引用: 1]

CAI D D, WANG S Q, LIAN P C, et al. Superhigh capacity and rate capability of high-level nitrogen-doped graphene sheets as anode materials for lithium-ion batteries[J]. Electrochimica Acta, 2013, 90: 492-497.

[本文引用: 1]

ZHAO J, GAO Y, LIU Q, et al. High rate capability and enhanced cyclability of Na3V2(PO4)2F3 cathode by in situ coating of carbon nanofibers for sodium-ion battery applications[J]. Chemistry, 2018, 24(12): 2913-2919.

[本文引用: 1]

DU P, MI K, HU F D, et al. Hierarchical hollow microspheres Na3V2(PO4)2F3C@rGO as high-performance cathode materials for sodium ion batteries[J]. New Journal of Chemistry, 2020, 44(30): 12985-12992.

[本文引用: 1]

LI Y S, LIANG X H, ZHONG G B, et al. Fiber-shape Na3V2(PO4)2F3@N-doped carbon as a cathode material with enhanced cycling stability for Na-ion batteries[J]. ACS Applied Materials & Interfaces, 2020, 12(23): 25920-25929.

PI Y Q, GAN Z W, YAN M Y, et al. Insight into pre-sodiation in Na3V2(PO4)2F3/C@ hard carbon full cells for promoting the development of sodium-ion battery[J]. Chemical Engineering Journal, 2021, 413: doi:10.1016/j.cej.1020.127565.

LIANG K, WANG S J, ZHAO H S, et al. A facile strategy for developing uniform hierarchical Na3V2(PO4)2F3@carbonized polyacrylonitrile multi-clustered hollow microspheres for high-energy-density sodium-ion batteries[J]. Chemical Engineering Journal, 2022, 428: doi:10.1016/j.cej.2022.131780.

ZHANG Y, WANG T, TANG Y K, et al. In situ redox reaction induced firmly anchoring of Na3V2(PO4)2F3 on reduced graphene oxide & carbon nanosheets as cathodes for high stable sodium-ion batteries[J]. Journal of Power Sources, 2021, 516: doi:10.1016/j.jPowsour.2021.230515.

LIU Q, MENG X, WEI Z X, et al. Core/double-shell structured Na3V2(PO4)2F3@C nanocomposite as the high power and long lifespan cathode for sodium-ion batteries[J]. ACS Applied Materials & Interfaces, 2016, 8(46): 31709-31715.

[本文引用: 2]

PARK Y U, SEO D H, KWON H S, et al. A new high-energy cathode for a Na-ion battery with ultrahigh stability[J]. Journal of the American Chemical Society, 2013, 135(37): 13870-13878.

[本文引用: 1]

WU F, ZHU N, BAI Y, et al. Unveil the mechanism of solid electrolyte interphase on Na3V2(PO4)3 formed by a novel NaPF6/BMITFSI ionic liquid electrolyte[J]. Nano Energy, 2018, 51: 524-532.

[本文引用: 1]

ZHAO J, YANG X, YAO Y, et al. Moving to aqueous binder: A valid approach to achieving high-rate capability and long-term durability for sodium-ion battery[J]. Advanced Science, 2018, 5(4): doi:10.1002/advs.201700768.

LI L, ZHANG N, SU Y Q, et al. Fluorine dissolution-induced capacity degradation for fluorophosphate-based cathode materials[J]. ACS Applied Materials & Interfaces, 2021, 13(20): 23787-23793.

HWANG J, MATSUMOTO K, HAGIWARA R. Electrolytes toward high-voltage Na3V2(PO4)2F3 positive electrode durable against temperature variation[J]. Advanced Energy Materials, 2020, 10(34): doi:10.1002/aenm.202001880.

[本文引用: 1]

ZHOU X, XIE Y, DENG Y F, et al. The enhanced rate performance of LiFe0.5Mn0.5PO4/C cathode material via synergistic strategies of surfactant-assisted solid state method and carbon coating[J]. Journal of Materials Chemistry A, 2015, 3(3): 996-1004.

[本文引用: 1]

YANG S L, HU M J, XI L J, et al. Solvothermal synthesis of monodisperse LiFePO4 micro hollow spheres as high performance cathode material for lithium ion batteries[J]. ACS Applied Materials & Interfaces, 2013, 5(18): 8961-8967.

[本文引用: 1]

YANG L, LIAO H X, TIAN Y, et al. Rod-like Sb2MoO6: Structure evolution and sodium storage for sodium-ion batteries[J]. Small Methods, 2019, 3(5): doi:10.1002/smtd.201800533.

/