物理化学学报 >> 2016, Vol. 32 >> Issue (9): 2293-2300.doi: 10.3866/PKU.WHXB201605201

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过充保护添加剂氰基功能化2, 5-二叔丁基对苯二酚的合成及其在锂离子电池中的应用

汪靖伦,闫晓丹,雍天乔,张灵志*()   

  • 收稿日期:2016-04-12 发布日期:2016-09-08
  • 通讯作者: 张灵志 E-mail:lzzhang@ms.giec.ac.cn
  • 基金资助:
    广东省科技计划(2014A050503050/2015B010135008);广州市科技计划(2014Y2-00012/201509010018);东莞市科技计划(2013509104210);王宽成教育基金会资助项目

Nitrile-Modified 2, 5-Di-tert-butyl-hydroquinones as Redox Shuttle Overcharge Additives for Lithium-Ion Batteries

Jing-Lun WANG,Xiao-Dan YAN,Tian-Qiao YONG,Ling-Zhi ZHANG*()   

  • Received:2016-04-12 Published:2016-09-08
  • Contact: Ling-Zhi ZHANG E-mail:lzzhang@ms.giec.ac.cn
  • Supported by:
    the Program of Guangdong Provincial Project for Science & Technology, China(2014A050503050/2015B010135008);Guangzhou Municipal Project for Science & Technology, China(2014Y2-00012/201509010018);Dongguan Municipal Project for Science & Technology, China(2013509104210);K. C. Wang Education Foundation, China

摘要:

设计合成了单氰基功能化的2, 5-二叔丁基-1-(β-氰基乙氧基)-4-甲氧基苯(RS-MCN)和双氰基功能化的2, 5-二叔丁基-1, 4-(β-氰基乙氧基)苯(RS-DCN),并用作氧化还原过充添加剂开展了其在锂离子电子中的应用研究。通过丙烯氰和2, 5-二叔丁基对苯二酚的迈克尔加成反应可高效合成RS-MCN和RS-DCN,氰乙基取代后的过充保护添加剂分子的可逆氧化还原电位分别为4.02、4.08 V(vs Li/Li+);并且单氰基取代的RS-MCN在商业碳酸酯电解液1 mol·L-1 LiPF6/EC+DEC+EMC(1:1:1,体积比)中的溶解度可高达0.3 mol·L-1。RSMCN和RS-DCN对LiFePO4/Li电池的过充保护性能和电极相容性也进行了深入的研究,实验结果表明:RSMCN具有更好的过充保护性能和电极相容性,其5 V截止电压过充保护时间可超过1200 h,100%过充保护大于90周循环;0.3 mol·L-1 RS-MCN的添加能使100%过充的LiFePO4/Li电池在2.5C倍率条件下正常循环,其放电比容量达153.5 mAh·g-1。此外,RS-MCN的添加对LiFePO4/Li电池在2.5-3.8 V条件下的循环性能有明显改善,添加有RS-MCN的电池在60周的循环后容量保持率高达94.4%,而商业电解液的电池在60周循环后的容量保持率降至84.3%。因此,氰基功能化RS-MCN是一类具有潜在应用前景的过充保护添加剂。

关键词: 锂离子电池, 电解液, 过充保护添加剂, 氰基, 2, 5-二叔丁基对苯二酚

Abstract:

Nitrile-modified 2, 5-di-tert-butyl-hydroquinones were synthesized and investigated as redox shuttle overcharge additives for LiFePO4/Li cells. The cyanoethylation reaction was utilized to synthesize the target molecules 2, 5-di-tert-butyl-1, 4-di(β-cyanoethoxyl)benzene (RS-DCN) and 2, 5-di-tert-butyl-1-(β-cyanoethoxyl)-4-methoxybenzene (RS-MCN) in high efficiency from 2, 5-di-tert-butyl-hydroquinone and acrylonitrile. The solubility, cyclic voltammetric measurements, 5 V overcharge test, 100% overcharge test, high rate performance under 100% overcharge conditions, and cycle performance under normal conditions were studied in detail for the electrolyte with the addition of RS-DCN or RS-MCN. The RS-MCN compounds with the asymmetric structure delivered better solubility (with max. 0.3 mol·L-1 in 1.0 mol·L-1 LiPF6/EC+DEC+EMC, 1 : 1 : 1, in vol.), higher overcharge protection life (over 1200 h for the 5 V overcharge test), and excellent rate performance under 100% overcharge conditions (specific discharge capacity reached 153.5 mAh·g-1 at 2.5C). The addition of RS-MCN also improved the cycling performance of the LiFePO4/Li cell under the charge-discharge voltage range of 2.5-3.8 V.

Key words: Lithium-ion battery, Electrolyte, Overcharge protection additive, Nitrile, 2, 5-Di-tert-butyl-hydroquinone

MSC2000: 

  • O646