本研究將工研院製備之無機陶瓷材料Li1.3Al0.3Ti1.7(PO4)3（LATP）與聚偏氟乙烯接枝聚醚基高分子進行混摻，兩者均具有離子傳導性，本實驗期望以具有較佳離子傳導度之 LATP作為主要離子傳導路徑，因此將陶瓷材料之重量比例拉升至複合固態電解質成膜之上限，並對不同陶瓷比例之電解質進行電化學性能及電池效能之比較。
聚偏氟乙烯接枝聚醚基高分子於複合系統中主要扮演黏著劑之角色，並同時具有離子傳導能力。聚偏氟乙烯作為高分子鏈段主體與一般 PEO高分子相比，其機械性質較佳，而接枝的聚醚官能基使此高分子亦具有離子傳導能力，其鋰離子可在陶瓷與高分子間作傳遞。因複合固態電解質內其高分子離子傳遞之能力也相對影響整體複合系統之電化學性能，因此本研究額外於複合系統內摻入塑化劑，此類型高分子/陶瓷複合固態電解質系統於 60°C下離子傳導度可達 10-4 Scm-1以上，電化學電位穩定窗則可達 5V以上。
然而此類型以無機材料為主體之複合電解質其與電極介面接觸性差，充放電時極化現象大，實際放電電容值偏低，且LATP之Ti4+和鋰金屬具反應性，使其長效循環充放之電容維持率不佳，因此透過交聯結構之聚醚類高分子混摻鋰鹽來修飾電極與複合電解質之介面，並隔絕LATP與鋰金屬直接接觸，形成交聯高分子/複合固態電解質/交聯高分子之三明治結構複合固態電解質。其於 60℃下，1C放電電容值可達 110.34 mAh g-1，相較於未修飾前之複合固態電解質 1C電容值 41.57 mAh g-1其效能有顯著的提升，且經長效循環充放 200圈後，電容維持率由 69.6%提升至 80.74%，綜觀以上表現可推知三明治結構之複合固態電解質適用於鋰金屬電池上。

In this study, Polyvinylidene Fluoride Grafted with Polyether/Li1.3Al0.3Ti1.7(PO4)3 (PVDF-g-PEO/LATP) composite electrolytes with and without oligomer were investigated. A high weight ratio of LATP is added into the composite solid electrolyte in order to form an effective pathway for lithium to transfer between the particles. The PVDF-g-PEO acts as no only a binder but also an ion conductor in this system. Membrane containing 70wt% of LATP and 30wt% of PVDF-g-PEO with oligomer exhibit ionic conductivity value of 2.24×10-4 S cm-1 at 60°C. And a stable electrochemical window above 5V can be obtained in the composite solid electrolyte, which is suitable for lithium batteries to use.
However, a large interfacial resistance is a main problem for the ceramic-based composite electrolytes. Also, LATP is unstable during contact with the Li metal. So we further modify cross-linked polymer layers between the electrodes and the composite solid electrolyte. Due to the modification by the polymer layers, the sandwich-structured composite solid electrolytes exhibit a higher discharge capacity at 1C ( 110.34 mAh g-1 at 60℃ ) and a better capacity retention ( 80.74% after 200th cycling ) .

1 Taracson, J. & Armand, M. Issues and challenges facing lithium ion batteries. nature 414, 359-367 (2001).
2 Lin, D., Liu, Y. & Cui, Y. Reviving the lithium metal anode for high-energy batteries. Nature nanotechnology 12, 194 (2017).
3 Di Pietro, B., Patriarca, M. & Scrosati, B. On the use of rocking chair configurations for cyclable lithium organic electrolyte batteries. Journal of Power Sources 8, 289-299 (1982).
4 Tagawa, K. & Brodd, R. J. in Lithium-ion batteries 181-194 (Springer, 2009).
5 Dunn, B., Kamath, H. & Tarascon, J.-M. Electrical energy storage for the grid: a battery of choices. Science 334, 928-935 (2011).
6 Padhi, A. K., Nanjundaswamy, K. S. & Goodenough, J. B. Phospho‐olivines as positive‐electrode materials for rechargeable lithium batteries. Journal of the electrochemical society 144, 1188-1194 (1997).
7 Li, W., Dahn, J. R. & Wainwright, D. S. Rechargeable lithium batteries with aqueous electrolytes. Science 264, 1115-1118 (1994).
8 Kato, Y. et al. High-power all-solid-state batteries using sulfide superionic conductors. Nature Energy 1, 16030 (2016).
9 Goodenough, J. B. & Park, K.-S. The Li-ion rechargeable battery: a perspective. Journal of the American Chemical Society 135, 1167-1176 (2013).
10 Manthiram, A., Yu, X. & Wang, S. Lithium battery chemistries enabled by solid-state electrolytes. Nature Reviews Materials 2, 16103 (2017).
11 Chen, R., Qu, W., Guo, X., Li, L. & Wu, F. The pursuit of solid-state electrolytes for lithium batteries: from comprehensive insight to emerging horizons. Materials Horizons 3, 487-516 (2016).
12 Stramare, S., Thangadurai, V. & Weppner, W. Lithium lanthanum titanates: a review. Chemistry of materials 15, 3974-3990 (2003).
13 Murugan, R., Thangadurai, V. & Weppner, W. Fast lithium ion conduction in garnet‐type Li7La3Zr2O12. Angewandte Chemie International Edition 46, 7778-7781 (2007).
14 Cheng, L. et al. Interrelationships among grain size, surface composition, air stability, and interfacial resistance of Al-substituted Li7La3Zr2O12 solid electrolytes. ACS applied materials & interfaces 7, 17649-17655 (2015).
15 Zhang, W., Nie, J., Li, F., Wang, Z. L. & Sun, C. A durable and safe solid-state lithium battery with a hybrid electrolyte membrane. Nano Energy 45, 413-419 (2018).
16 Fenton, D. Complexes of alkali metal ions with poly (ethylene oxide). polymer 14, 589 (1973).
17 Vashishta, P., Mundy, J. N. & Shenoy, G. Fast ion transport in solids: electrodes and electrolytes. (1979).
18 Xue, Z., He, D. & Xie, X. Poly (ethylene oxide)-based electrolytes for lithium-ion batteries. Journal of Materials Chemistry A 3, 19218-19253 (2015).
19 Zhang, Q., Liu, K., Ding, F. & Liu, X. Recent advances in solid polymer electrolytes for lithium batteries. Nano Research 10, 4139-4174 (2017).
20 Golodnitsky, D., Strauss, E., Peled, E. & Greenbaum, S. On order and disorder in polymer electrolytes. Journal of The Electrochemical Society 162, A2551-A2566 (2015).
21 Baskaran, R., Selvasekarapandian, S., Kuwata, N., Kawamura, J. & Hattori, T. Conductivity and thermal studies of blend polymer electrolytes based on PVAc–PMMA. Solid State Ionics 177, 2679-2682 (2006).
22 Kim, G.-T. et al. UV cross-linked, lithium-conducting ternary polymer electrolytes containing ionic liquids. Journal of Power Sources 195, 6130-6137 (2010).
23 Appetecchi, G. & Scrosati, B. A lithium ion polymer battery. Electrochimica acta 43, 1105-1107 (1998).
24 Gopalan, A. I. et al. Development of electrospun PVdF–PAN membrane-based polymer electrolytes for lithium batteries. Journal of membrane science 325, 683-690 (2008).
25 Ulaganathan, M. & Rajendran, S. Effect of different salts on PVAc/PVdF‐co‐HFP based polymer blend electrolytes. Journal of applied polymer science 118, 646-651 (2010).
26 Dudney, N., Bates, J., Zuhr, R., Luck, C. & Robertson, J. Sputtering of lithium compounds for preparation of electrolyte thin films. solid state ionics 53, 655-661 (1992).
27 Wang, M. & Sakamoto, J. Correlating the interface resistance and surface adhesion of the Li metal-solid electrolyte interface. Journal of Power Sources 377, 7-11 (2018).
28 Bachman, J. C. et al. Inorganic solid-state electrolytes for lithium batteries: mechanisms and properties governing ion conduction. Chemical reviews 116, 140-162 (2015).
29 Cushing, B. L. & Goodenough, J. B. Li2NaV2 (PO4) 3: A 3.7 V lithium-insertion cathode with the rhombohedral NASICON structure. Journal of Solid State Chemistry 162, 176-181 (2001).
30 Cheng, Q. et al. Stabilizing Solid Electrolyte-Anode Interface in Li-Metal Batteries by Boron Nitride-Based Nanocomposite Coating. Joule 3, 1510-1522 (2019).
31 Zhao, E., Ma, F., Guo, Y. & Jin, Y. Stable LATP/LAGP double-layer solid electrolyte prepared via a simple dry-pressing method for solid state lithium ion batteries. Rsc Advances 6, 92579-92585 (2016).
32 Zhang, Y., Chen, F., Tu, R., Shen, Q. & Zhang, L. Field assisted sintering of dense Al-substituted cubic phase Li7La3Zr2O12 solid electrolytes. Journal of Power Sources 268, 960-964 (2014).
33 Thompson, T. et al. Tetragonal vs. cubic phase stability in Al–free Ta doped Li 7 La 3 Zr 2 O 12 (LLZO). Journal of Materials Chemistry A 2, 13431-13436 (2014).
34 Cheng, L. et al. The origin of high electrolyte–electrode interfacial resistances in lithium cells containing garnet type solid electrolytes. Physical Chemistry Chemical Physics 16, 18294-18300 (2014).
35 Xia, W. et al. Ionic conductivity and air stability of Al-doped Li7La3Zr2O12 sintered in alumina and Pt crucibles. ACS applied materials & interfaces 8, 5335-5342 (2016).
36 Bernuy-Lopez, C. et al. Atmosphere controlled processing of Ga-substituted garnets for high Li-ion conductivity ceramics. Chemistry of materials 26, 3610-3617 (2014).
37 Weston, J. & Steele, B. Effects of inert fillers on the mechanical and electrochemical properties of lithium salt-poly (ethylene oxide) polymer electrolytes. Solid State Ionics 7, 75-79 (1982).
38 Sarnowska, A., Polska, I., Niedzicki, L., Marcinek, M. & Zalewska, A. Properties of poly (vinylidene fluoride-co-hexafluoropropylene) gel electrolytes containing modified inorganic Al2O3 and TiO2 filler, complexed with different lithium salts. Electrochimica Acta 57, 180-186 (2011).
39 Wang, Y.-J. & Kim, D. Crystallinity, morphology, mechanical properties and conductivity study of in situ formed PVdF/LiClO4/TiO2 nanocomposite polymer electrolytes. Electrochimica acta 52, 3181-3189 (2007).
40 Kim, K. M., Park, N.-G., Ryu, K. S. & Chang, S. H. Characteristics of PVdF-HFP/TiO2 composite membrane electrolytes prepared by phase inversion and conventional casting methods. Electrochimica Acta 51, 5636-5644 (2006).
41 Fu, X. et al. Inorganic and organic hybrid solid electrolytes for lithium-ion batteries. CrystEngComm 18, 4236-4258 (2016).
42 Zhang, Q., Ding, F., Sun, W. & Sang, L. Preparation of LAGP/P (VDF-HFP) polymer electrolytes for Li-ion batteries. Rsc Advances 5, 65395-65401 (2015).
43 Chen, L. et al. PEO/garnet composite electrolytes for solid-state lithium batteries: From “ceramic-in-polymer” to “polymer-in-ceramic”. Nano Energy 46, 176-184 (2018).
44 Pittenger, B., Erina, N. & Su, C. Quantitative mechanical property mapping at the nanoscale with PeakForce QNM. Application Note Veeco Instruments Inc, 1-2 (2010).
45 Samanta, S., Chatterjee, D. P., Layek, R. K. & Nandi, A. K. Nano-structured poly (3-hexyl thiophene) grafted on poly (vinylidene fluoride) via poly (glycidyl methacrylate). Journal of Materials Chemistry 22, 10542-10551 (2012).
46 Yang, L. et al. Flexible Composite Solid Electrolyte Facilitating Highly Stable “Soft Contacting” Li–Electrolyte Interface for Solid State Lithium-Ion Batteries. Advanced Energy Materials 7, 1701437, doi:10.1002/aenm.201701437 (2017).
47 Li, D., Chen, L., Wang, T. & Fan, L.-Z. 3D fiber-network-reinforced bicontinuous composite solid electrolyte for dendrite-free lithium metal batteries. ACS applied materials & interfaces 10, 7069-7078 (2018).
48 Zheng, J., Dang, H., Feng, X., Chien, P.-H. & Hu, Y.-Y. Li-ion transport in a representative ceramic–polymer–plasticizer composite electrolyte: Li 7 La 3 Zr 2 O 12–polyethylene oxide–tetraethylene glycol dimethyl ether. Journal of Materials Chemistry A 5, 18457-18463 (2017).
49 Cho, S., Kim, S., Kim, W., Kim, S. & Ahn, S. All-Solid-State Lithium Battery Working without an Additional Separator in a Polymeric Electrolyte. Polymers 10, 1364 (2018).
50 Cheng, Q. et al. Stabilizing Solid Electrolyte-Anode Interface in Li-Metal Batteries by Boron Nitride-Based Nanocomposite Coating. Joule (2019).
51 Li, H. et al. A sandwich structure polymer/polymer-ceramics/polymer gel electrolytes for the safe, stable cycling of lithium metal batteries. Journal of Membrane Science 555, 169-176, doi:10.1016/j.memsci.2018.03.038 (2018).