纳米锂镧锆钽氧粉体复合聚氧化乙烯制备的固态电解质电化学性能的研究

doi:10.12028/j.issn.2095-4239.2016.0032

摘要/Abstract

摘要： 与采用液体电解液的传统二次锂离子电池相比，固态二次锂电池在高能量密度和安全性方面具有显著的潜在优势，近年来成为国内外的研究热点。作为固态二次锂电池的核心组成，固态电解质需要具备高离子电导率、宽电化学窗口、对锂稳定、力学性能优以及可抑制锂枝晶等特性。为达到以上要求，本工作探索制备了由纳米钽掺杂锂镧锆氧（LLZTO）粉体与聚氧化乙烯（PEO）复合的有机-无机复合固态电解质膜材料，对比研究了在有机物PEO中添加锂盐和不添加锂盐对固态电解质膜电导率及电化学特性的影响。发现在PEO-LLZTO复合电解质膜中，虽然PEO不导电，但界面处存在的渗流效应可极大提高膜的总电导率，室温离子电导率可达到2×104 S/cm。这一数值虽然略低于PEO-LiTFSI-LLZTO复合电解质膜（室温条件下电导率为6×104 S/cm），但无锂盐添加的PEO-LLZTO复合电解质膜表现出较好的电化学稳定性和较强的抑制锂枝晶的能力。将PEO-LLZTO复合电解质膜与Li/LiFePO4和Li/LiFe0.15Mn0.85PO4组装成软包电池，在0.1 C、60 ℃的测试条件下可充分发挥正极材料的容量，并可稳定循环200次以上。

关键词: 固态电解质, 聚氧化乙烯, LLZTO纳米粉, 渗流效应

Abstract: Compared to the commercial rechargeable lithium batteries using liquid electrolytes, the rechargeable solid state lithium batteries have attracted much attention, since their great potential in high energy density and safety. As the key materials for rechargeable solid state lithium batteries, the solid state electrolytes need to have the high ionic conductivity, wide electrochemical window, superior mechanical properties, stability against Li and ability to suppressing lithium dendrite growth. To meet the above requirements, organic-inorganic hybrid solid state electrolytes membranes with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanopowders and polyethylene oxides (PEO) are prepared. The conductivity and electrochemical properties of PEO-LLZTO and PEO-LiTFSI-LLZTO membranes are comparatively studied. With the insulating PEO, the conductivities of the PEO-LLZTO electrolytes membranes have been greatly improved owing to the percolation effect at the interface, approaching 2×10−4 S/cm at room temperature. Though the conductivity of the PEO-LLZTO electrolytes membranes is slightly lower than that of the PEO-LiTFSI-LLZTO electrolyte membranes (i.e. 6×10−4 S/cm at room temperature), the PEO-LLZTO electrolyte membranes show better electrochemical stability and improved ability of suppressing the lithium dendrite growth. The pouch cells using PEO-LLZTO electrolytes membranes with Li/LiFePO4 and Li/LiFe0.15Mn0.85PO4 show higher energy density, and the batteries can cycle more than 200 times.

Key words: solid state electrolytes, PEOs, LLZTO nanopowders, percolation effect

赵宁1，李忆秋1，郭向欣1，张静娴2，狄增峰2. 纳米锂镧锆钽氧粉体复合聚氧化乙烯制备的固态电解质电化学性能的研究[J]. 储能科学与技术, 2016, 5(5): 754-761.

ZHAO Ning1, LI Yiqiu1, GUO Xiangxin1, ZHANG Jingxian2, DI Zengfeng2. Electroc hemical performance of solid state electrolytes consisting of Li6.4La3Zr1.4Ta0.6O12 nanopowders dispersed in polyethylene oxides[J]. Energy Storage Science and Technology, 2016, 5(5): 754-761.

参考文献

[1] TARASCON J M，ARMAND M. Issues and challenges facing rechargeable lithium batteries[J]. Nature，2001，414（6861）：359-367.

[2] OHTA N，TAKADA K，ZHANG L，et al. Enhancement of the high-rate capability of solid-state lithium batteries by nanoscale interfacial modification[J]. Advanced Materials，2006，18（17）：2226-2229.

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

[4] HOVINGTON P，LAGACÉ M，GUERFI A，et al. New lithium metal polymer solid state battery for an ultrahigh energy：Nano C-LiFePO₄ versus nano Li_1.2V₃O₈[J]. Nano Letters，2015，15（4）：2671-2678.

[5] KAMAYA N，HOMMA K，YAMAKAWA Y，et al. A lithium superionic conductor[J]. Nature Materials，2011，10（9）：682-686.

[6] KATO Y，HORI S，SAITO T，et al. High-power all-solid-state batteries using sulfide superionic conductors[J]. Nature Energy，2016，1：doi:10.1038/nenergy.2016.30.

[7] DENG Y，EAMES C，CHOTARD J N，et al. Structural and mechanistic insights into fast lithium-ion conduction in Li₄SiO₄-Li₃PO₄ solid electrolytes[J]. Journal of the American Chemical Society，2015，137（28）：9136-9145.

[8] DENG Z，RADHAKRISHNAN B，ONG S P. Rational composition optimization of the lithium-rich Li₃OCl_1–xBr_x anti-perovskite superionic conductors[J]. Chemistry of Materials，2015，27（10）：3749-3755.

[9] ADACHI G，IMANAKA N，AONO H. Fast Li⊕ conducting ceramic electrolytes[J]. Advanced Materials，1996，8（2）：127-135.

[10] KNAUTH P. Inorganic solid Li ion conductors：An overview[J]. Solid State Ionics，2009，180（14）：911-916.

[11] GOODENOUGH J B，SINGH P. Review-solid electrolytes in rechargeable electrochemical cells[J]. Journal of the Electrochemical Society，2015，162（14）：A2387-A2392.

[12] LI Y，WANG Z，CAO Y，et al. W-doped Li₇La₃Zr₂O₁₂ ceramic electrolytes for solid state Li-ion batteries[J]. Electrochimica Acta，2015，180：37-42.

[13] CHEN R J，HUANG M，HUANG W Z，et al. Effect of calcining and Al doping on structure and conductivity of Li₇La₃Zr₂O₁₂[J]. Solid State Ionics，2014，265：7-12.

[14] HUANG M，SHOJI M，SHEN Y，et al. Preparation and electrochemical properties of Zr-site substituted Li₇La₃(Zr₂_-_xM_x)O₁₂ (M=Ta, Nb) solid electrolytes[J]. Journal of Power Sources，2014，261：206-211.

[15] QUARTARONE E，MUSTARELLI P，MAGISTRIS A. PEO-based composite polymer electrolytes[J]. Solid State Ionics，1998，110（1）：1-14.

[16] AHN J H，WANG G X，LIU H K，et al. Nanoparticle-dispersed PEO polymer electrolytes for Li batteries[J]. Journal of Power Sources，2003，119：422-426.

[17] DENG F，WANG X，HE D，et al. Microporous polymer electrolyte based on PVDF/PEO star polymer blends for lithium ion batteries[J]. Journal of Membrane Science，2015，491：82-89.

[18] WALKER C W，SALOMON M. Improvement of ionic conductivity in plasticized PEO-based solid polymer electrolytes[J]. Journal of the Electrochemical Society，1993，140（12）：3409-3412.

[19] ANGELL C A，XU K，ZHANG S S，et al. Variations on the salt-polymer electrolyte theme for flexible solid electrolytes[J]. Solid State Ionics，1996，86：17-28.

[20] FERGUS J W. Ceramic and polymeric solid electrolytes for lithium-ion batteries[J]. Journal of Power Sources，2010，195（15）：4554-4569.

[21] QUARTARONE E，MUSTARELLI P，MAGISTRIS A. PEO-based composite polymer electrolytes[J]. Solid State Ionics，1998，110（1）：1-14.

[22] ZHANG H，LIU C，ZHENG L，et al. Lithium bis(fluorosulfonyl) imide/poly(ethylene oxide) polymer electrolyte[J]. Electrochimica Acta，2014，133：529-538.

[23] BERTHIER C，GORECKI W，MINIER M，et al. Microscopic investigation of ionic conductivity in alkali metal salts-poly(ethylene oxide) adducts[J]. Solid State Ionics，1983，11（1）：91-95.

[24] CROCE F，APPETECCHI G B，PERSI L，et al. Nanocomposite polymer electrolytes for lithium batteries[J]. Nature，1998，394（6692）：456-458.

[25] MEYER W H. Polymer electrolytes for lithium-ion batteries[J]. Advanced Materials，1998，10（6）：439-448.

[26] KETABI S，LIAN K. Effect of SiO₂ on conductivity and structural properties of PEO-EMIHSO₄ polymer electrolyte and enabled solid electrochemical capacitors[J]. Electrochimica Acta，2013，103：174-178.

[27] FAN L，NAN C W，ZHAO S. Effect of modified SiO₂ on the properties of PEO-based polymer electrolytes[J]. Solid State Ionics，2003，164（1）：81-86.

[28] KIM J W，JI K S，LEE J P，et al. Electrochemical characteristics of two types of PEO-based composite electrolyte with functional SiO₂[J]. Journal of Power Sources，2003，119：415-421.

[29] FULLERTON-SHIREY S K，MARANAS J K. Structure and mobility of PEO/LiClO₄ solid polymer electrolytes filled with Al₂O₃ nanoparticles[J]. The Journal of Physical Chemistry C，2010，114（20）：9196-9206.

[30] JOHAN M R，SHY O H，IBRAHIM S，et al. Effects of Al₂O₃ nanofiller and EC plasticizer on the ionic conductivity enhancement of solid PEO-LiCF₃SO₃ solid polymer electrolyte[J]. Solid State Ionics，2011，196（1）：41-47.

[31] LI Q，TAKEDA Y，IMANISH N，et al. Cycling performances and interfacial properties of a Li/PEO-Li(CF₃SO₂)₂ N-ceramic filler/LiNi_0.8Co_0.2O₂ cell[J]. Journal of Power Sources，2001，97：795-797.

[32] PITAWALA H，DISSANAYAKE M，SENEVIRATNE V A. Combined effect of Al₂O₃ nano-fillers and EC plasticizer on ionic conductivity enhancement in the solid polymer electrolyte (PEO)₉LiTf[J]. Solid State Ionics，2007，178（13）：885-888.

[33] VIGNAROOBAN K，DISSANAYAKE M，ALBINSSON I，et al. Effect of TiO₂ nano-filler and EC plasticizer on electrical and thermal properties of poly(ethylene oxide) (PEO) based solid polymer electrolytes[J]. Solid State Ionics，2014，266：25-28.

[34] KETABI S，LIAN K. The effects of SiO₂ and TiO₂ nanofillers on structural and electrochemical properties of poly(ethylene oxide)-EMIHSO₄ electrolytes[J]. Electrochimica Acta，2015，154：404-412.

[35] DU F，ZHAO N，LI Y，et al. All solid state lithium batteries based on lamellar garnet-type ceramic electrolytes[J]. Journal of Power Sources，2015，300：24-28.

[36] JOHAN M R，FEN L B. Combined effect of CuO nanofillers and DBP plasticizer on ionic conductivity enhancement in the solid polymer electrolyte PEO-LiCF₃SO₃[J]. Ionics，2010，16（4）：335-338.

[37] ALLEN J L，WOLFENSTINE J，RANGASAMY E，et al. Effect of substitution (Ta, Al, Ga) on the conductivity of Li₇La₃Zr₂O₁₂[J]. Journal of Power Sources，2012，206：315-319.

[38] BHATTACHARYYA A J，MAIER J. Second phase effects on the conductivity of non-aqueous salt solutions：“soggy sand electrolytes”[J]. Advanced Materials，2004，16（9/10）：811-814.