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Lithium-free lithium ion battery cathode material Na3V2(PO4)3/C and preparation method thereof

A technology of lithium ion battery and composite cathode material, applied in the field of electrochemical power supply, can solve problems such as unsatisfactory performance and poor conductivity, and achieve the effects of low cost, high specific capacity and easy operation

Active Publication Date: 2017-12-15
江苏国锂能源科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to its poor conductivity, Na 3 V 2 (PO 4 ) 3 performance is not ideal

Method used

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  • Lithium-free lithium ion battery cathode material Na3V2(PO4)3/C and preparation method thereof
  • Lithium-free lithium ion battery cathode material Na3V2(PO4)3/C and preparation method thereof
  • Lithium-free lithium ion battery cathode material Na3V2(PO4)3/C and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 称取3mmol碳酸钠、2mmol五氧化二钒、5mmol六次甲基四胺溶于装有20mL去离子水的小烧杯中,搅拌30min至其充分溶解;将得到的混合溶液转移至水热内胆中,添加去离子水至内胆体积的80%,之后在140℃的鼓风烘箱中水热24h,自然冷却得到中间相液体。称取0.05g柠檬酸和6mmol磷酸二氢铵溶于装有20mL去离子水的烧杯中,搅拌20min至其充分溶解,之后缓慢向烧杯中滴加冷却后的中间相液体,滴加完毕后搅拌30min至橙黄色。将装有液体的烧杯放置于80℃的鼓风烘箱中24h烘干。将烘干后的前驱体研磨成粉末,于氮气气氛下350℃预烧4h,并在750℃下煅烧8h,自然冷却后得到Na 3 V 2 (PO 4 ) 3 / C复合材料。对材料进行SEM表征,由 figure 1 可以看出,其形貌为复合形貌,由尺寸约300nm的颗粒和尺寸约1μm的片状构成。将上述步骤得到的Na 3 V 2 (PO 4 ) 3 / C复合材料与导电剂、粘结剂混合(质量比7.5:1.5:1,Na 3 V 2 (PO 4 ) 3 / C:乙炔黑:PVDF),涂覆在铝箔上裁剪成14mm的圆片,在120℃下真空干燥12h。以金属锂片为对电极,Celgard膜为隔膜,溶解有LiPF 6 (1mol / L) 的EC+DEC(体积比为1:1)的溶液为电解液,在氩气保护的手套箱中组装成CR2025型电池。电池组装完后静置8h,再用CT2001A电池测试系统进行恒流充、放电测试,测试电压为3-4.3V。 figure 2 表明,实施例 1 所制备的Na 3 V 2 (PO 4 ) 3 / C电极首次充、放电容量分别为115.7和110.7 mAh / g,100次循环之后充、放电容量分别为103.5和103 mAh / g,显示了较好的电化学性能。

Embodiment 2

[0019] 称取6mmol醋酸钠、2mmol五氧化二钒、5mmol六次甲基四胺溶于装有20mL去离子水的小烧杯中,搅拌30min至其充分溶解;将得到的混合溶液转移至水热内胆中,添加去离子水至内胆体积的80%,之后在120℃的鼓风烘箱中水热24h,自然冷却得到中间相液体。称取0.05g葡萄糖和6mmol磷酸二氢铵溶于装有20mL去离子水的烧杯中,搅拌20min至其充分溶解,之后缓慢向烧杯中滴加冷却后的中间相液体,滴加完毕后搅拌30min至颜色呈橙黄色。之后将装有液体的烧杯放置于80℃的鼓风烘箱中24h烘干。将烘干后的前驱体研磨成粉末,于氮气气氛下350℃预烧4h,并在750℃下煅烧8h,自然冷却后得到Na 3 V 2 (PO 4 ) 3 / C Composite. Electrodes were prepared and batteries were assembled in the manner of Example 1. image 3 It shows that the Na prepared in Example 2 3 V 2 (PO 4 ) 3 The initial charge and discharge capacities of the / C electrode are 117.2 and 113.1 mAh / g, respectively, and after 100 cycles, the charge and discharge capacities are 109.7 and 107.8 mAh / g, respectively, showing good electrochemical performance.

Embodiment 3

[0021] Weigh 6mmol of sodium hydroxide, 2mmol of vanadium pentoxide, and 5mmol of hexamethylenetetramine and dissolve them in a small beaker filled with 20mL of deionized water, stir for 30min until they are fully dissolved; transfer the obtained mixed solution to a hydrothermal In the tank, add deionized water to 80% of the volume of the inner tank, then heat it in a blast oven at 140°C for 24 hours, and cool naturally to obtain a mesophase liquid. Weigh 0.05g sucrose and 6mmol ammonium dihydrogen phosphate and dissolve them in a beaker filled with 20mL deionized water, stir for 20min until they are fully dissolved, then slowly add the cooled intermediate phase liquid into the beaker, and stir for 30min after the addition is complete until the color is orange-yellow. Afterwards, place the beaker containing the liquid in a blast oven at 80°C for 24 hours to dry. The dried precursor was ground into powder, pre-calcined at 350 °C for 4 h in a nitrogen atmosphere, calcined at 75...

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Abstract

The invention provides an intermediate liquid phase method for preparation of a carbon compound sodium vanadium phosphate lithium ion battery cathode material. The specific steps include: weighing a sodium source and a vanadium source into a small beaker, adding deionized water, performing stirring for 30min till complete dissolution, transferring the mixture into a hydrothermal liner, adding deionized water to 80% of the liner volume, and conducting hydrothermal treatment in a blast oven at 100-180DEG C for 12-48h; weighing a phosphorus source and an organic carbon source in a beaker, adding deionized water, performing stirring for 20min till complete dissolution, then adding a naturally cooled intermediate phase liquid slowly into the beaker holding the dissolved phosphorus source and organic carbon source dropwise, conducting stirring for 20min until the solution turns into orange yellow, and performing drying in a 80DEG C blast oven for 24h; and grinding a precursor into powder, performing presintering in a nitrogen atmosphere at 350DEG C for 2-6h, also conducting calcinations at 650-850DEG C for 6-12h, and performing natural cooling to obtain the Na3V2(PO4)3 / C composite material. The Na3V2(PO4)3 / C composite material can show good electrochemical properties when used as a lithium ion battery cathode.

Description

technical field [0001] 本发明涉及一类高性能锂离子电池正极材料,特别涉及一种Na 3 V 2 (PO 4 ) 3 / C复合材料的制备方法,属于电化学电源领域。 technical background [0002] 锂离子电池具有高能量密度、高安全性能、低自放电、长寿命、无记忆等优点,目前已经成为便携电子产品的主要电源。未来,还有可能被应用于电动汽车、混合动力汽车、军用设备及储能电网。正极作为锂离子电池的重要组成部分,其性能直接决定锂离子电池的性能,从某种程度上说,它直接决定了锂离子电池成本的高低。因此,研究高性能的正极材料是研制高性能锂离子电池的重要任务。 [0003] 随着锂离子电池的大规模应用,锂资源需求将迅速增加,将伴随着锂源的价格不断上涨,这不利于锂离子电池的可持续发展。 目前所研究的正极材料大多为锂过渡金属化合物。 Na 3 V 2 (PO 4 ) 3 作为一种含钠不含锂的锂离子电池正极材料,较含锂的正极材料具有天然的价格优势,且Na 3 V 2 (PO 4 ) 3 作为磷酸基的电极材料,具有卓越的热稳定性和电化学稳定性,这为优异的循环性能提供了基础。 Na 3 V 2 (PO 4 ) 3 具有NASICON框架结构,是一种快离子导体材料,这种材料具有三维开放离子运输通道,作为锂离子电池电极材料时具有较高的锂离子扩散速度。然而,受制于其较差的导电性,Na 3 V 2 (PO 4 ) 3 的性能并不理想。增强电极材料导电性的最常用方式为与碳材料如碳纳米管,石墨烯,石墨等复合。而电极材料与碳在微观尺度的复合均匀程度将是决定复合材料最终导电性的关键。 [0004] 基于以上背景,本专利发明一种中间液相方法,制备碳与Na 3 V 2 (PO 4 ) 3 在微观尺度均匀复合的锂离子电池复合正极材料,显著提升Na 3 V 2 (PO 4 ) 3 导电性。首先通过水热法制备中间相液体,然后向其中引入碳源。液相有利于碳源与反应原料均匀复合,烘干过程中中间相液体结晶将诱导碳源分子在其表面吸附;在随后固相反应中,Na 3 V 2 (PO 4 ) 3 形成的同时,碳源分子沿Na 3 V 2 (PO 4 ) 3 表面原位炭化。最终,将形成Na ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/362H01M4/5825H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 倪世兵唐俊陈启长杨学林
Owner 江苏国锂能源科技有限公司