Dual-lithium-salt Gel Complex Electrolyte: Preparation and Application in Lithium-metal Battery

doi:10.15541/jim20220761

Abstract

Abstract:

Metallic Li is one of the ideal anodes for high energy density lithium-ion battery due to its high theoretical specific capacity, low reduction potential as well as abundant reserves. However, the application of Li anodes suffer from serious incompatibility with traditional organic liquid electrolyte. Herein, a gel complex electrolyte (GCE) with satisfactory compatibility with metallic Li anode was constructed via in situ polymerization. The double lithium salt system introduced into the electrolyte can cooperate with the polymer component, which broadens electrochemical window of the electrolyte to 5.26 V compared to 3.92 V of commercial electrolyte, and obtains a high ionic conductivity of 1×10^-3 S·cm^-1 at 30 ℃ as well. Results of morphology characterization and elemental analysis of Li anode surface show that GCE exhibits obvious protective effect on lithium metal under the condition of double lithium salt system, and volume effect and dendrite growth of Li anode are obviously inhibited. At the same time, the lithium metal full battery, assembled with commercial lithium iron phosphate (LiFePO₄) cathode material, exhibits excellent cycling stability and rate performance. The capacity retention rate of the battery reaches 92.95 % after 200 cycles at a constant current of 0.2C (1C = 0.67 mA·cm^-2) at 25 ℃. This study indicates that the GCE can effectively improve the safety, stability and comprehensive electrochemical performance of lithium-metal battery, which is expected to provide a strategy for universal quasi-solid electrolyte design.

Key words: metallic Li, in-situ polymerization, gel complex electrolyte

CLC Number:

TM911

GUO Yuxiang, HUANG Liqiang, WANG Gang, WANG Hongzhi. Dual-lithium-salt Gel Complex Electrolyte: Preparation and Application in Lithium-metal Battery[J]. Journal of Inorganic Materials, 2023, 38(7): 785-792.

Figures/Tables 9

Fig. 1 Preparation and structural analysis of GCE (a) Polymerization reaction of PEGDA; (b) Optical photographs of GCE-x; (c, d) FT-IR spectra of GCE-20, PEGDA and LE; (e) XRD patterns of GCE-x; Colorful figures are available on website

Fig. 2 Electrochemical performance of GCE-20 (a) Ionic conductivities of LE and GCE-20; (b) LSV curves of LE and GCE-20; (c) Current-time profile of Li|GCE-20|Li cell with inset showing corresponding Nyquist plots; (d) Voltage-time curves of symmetric Li||Li cells assembled with LE and GCE-20; (e) Nyquist plots of Li|GCE-20|Li cell after cycling; (f) Voltage-time and current density-time curves of Li|GCE-20|Li cell; Colorful figures are available on website

Fig. 3 SEM images of metallic Li Cross-sectional (up) and top-view (down) SEM images of (a) fresh metallic Li and lithium deposition morphology in symmetric Li||Li cells with (b) LE and (c) GCE-20

Fig. 4 Electrochemical performance of the Li|GCE-20|LiFePO4 cells (a) Cycling performance and (b) corresponding voltage-capacity curves at 0.2C; (c) Rate performance and (d) corresponding voltage-capacity curves; Colorful figures are available on website

Fig. S1 Contact angles between polymer precursor solution and cathodes (a) LE; (b) GCE-10; (c) GCE-20; (d) GCE-30

Fig. S2 Nyquist plots of GCE assembled Li||LiFePO4 cells with different lithium salt

Fig. S3 Nyquist plots of symmetric Li||Li cells assembled with GCE-x electrolytes

Fig. S4 Voltage-time profiles of symmetric Li||Li cells assembled with GCE-x electrolytes

Fig. S5 XPS spectra of metallic Li anode in symmetric Li||Li cells (a, d) C1s, (b, e) O1s, (c, f) F1s XPS spectra of metallic Li anode with (a-c) LE and (d-f) GCE-20

References 32

[1]	GOODENOUGH J B, KIM Y. Challenges for rechargeable Li batteries. Chemistry of Materials, 2010, 22(3):587. DOI URL
[2]	ZHAO J, LIAO L, SHI F, et al. Surface fluorination of reactive battery anode materials for enhanced stability. Journal of the American Chemical Society, 2017, 139(33):11550. DOI PMID
[3]	TARASCON J M, ARMAND M. Issues and challenges facing rechargeable lithium batteries. Nature, 2001, 414(6861):359. DOI URL
[4]	ZHI J, YAZDI A Z, VALAPPIL G, et al. Artificial solid electrolyte interphase for aqueous lithium energy storage systems. Science Advances, 2017, 3(9):e1701010. DOI URL
[5]	JUN K, SUN Y, XIAO Y, et al. Lithium superionic conductors with corner-sharing frameworks. Nature Materials, 2022, 21: 924.
[6]	LIU J, BAO Z, CUI Y, et al. Pathways for practical high-energy long-cycling lithium metal batteries. Nature Energy, 2019, 4(3):180. DOI
[7]	DUNN B, KAMATH H, TARASCON J M. Electrical energy storage for the grid: a battery of choices. Science, 2011, 334(6058):928. DOI PMID
[8]	MAUGER A, JULIEN C M, PAOLELLA A, et al. Building better batteries in the solid state: a review. Materials, 2019, 12(23):3892. DOI URL
[9]	MANTHIRAM A, YU X, WANG S. Lithium battery chemistries enabled by solid-state electrolytes. Nature Reviews Materials, 2017, 2(4):16103. DOI
[10]	ZHOU D, SHANMUKARAJ D, TKACHEVA A, et al. Polymer electrolytes for lithium-based batteries: advances and prospects. Chem, 2019, 5(9):2326. DOI
[11]	TAN S J, YUE J, TIAN Y F, et al. In-situ encapsulating flame- retardant phosphate into robust polymer matrix for safe and stable quasi-solid-state lithium metal batteries. Energy Storage Materials, 2021, 39: 186.
[12]	ZHAO Q, LIU X, STALIN S, et al. Solid-state polymer electrolytes with in-built fast interfacial transport for secondary lithium batteries. Nature Energy, 2019, 4(5):365. DOI
[13]	ZHOU Z, FENG Y, WANG J, et al. A robust, highly stretchable ion-conducive skin for stable lithium metal batteries. Chemical Engineering Journal, 2020, 396: 125254.
[14]	WILKEN S, TRESKOW M, SCHEERS J, et al. Initial stages of thermal decomposition of LiPF₆-based lithium ion battery electrolytes by detailed Raman and NMR spectroscopy. RSC Advances, 2013, 3(37):16359. DOI URL
[15]	LIU F Q, WANG W P, YIN Y X, et al. Upgrading traditional liquid electrolyte via in situ gelation for future lithium metal batteries. Science Advances, 2018, 4(10):eaat5383. DOI URL
[16]	XU C, SUN B, GUSTAFSSON T, et al. Interface layer formation in solid polymer electrolyte lithium batteries: an XPS study. Journal of Materials Chemistry A, 2014, 2(20):7256. DOI URL
[17]	WEI Z, CHEN S, WANG J, et al. Superior lithium ion conduction of polymer electrolyte with comb-like structure via solvent-free copolymerization for bipolar all-solid-state lithium battery. Journal of Materials Chemistry A, 2018, 6(27):13438. DOI URL
[18]	DI NOTO V, LAVINA S, GIFFIN G A, et al. Polymer electrolytes: present, past and future. Electrochimica Acta, 2011, 57(15):4. DOI URL
[19]	XUE Z, HE D, XIE X. Poly(ethylene oxide)-based electrolytes for lithium-ion batteries. Journal of Materials Chemistry A, 2015, 3(38):19218. DOI URL
[20]	MINDEMARK J, LACEY M J, BOWDEN T, et al. Beyond PEO-Alternative host materials for Li⁺-conducting solid polymer electrolytes. Progress in Polymer Science, 2018, 81: 114.
[21]	ARAVINDAN V, GNANARAJ J, MADHAVI S, et al. Lithium-ion conducting electrolyte salts for lithium batteries. Chemistry-A European Journal, 2011, 17(51):14326.
[22]	XU K. Electrolytes and interphases in Li-ion batteries and beyond. Chemical Reviews, 2014, 114(23):11503. DOI PMID
[23]	YANG H, ZHUANG G V, ROSS JR P N. Thermal stability of LiPF₆ salt and Li-ion battery electrolytes containing LiPF₆. Journal of Power Sources, 2006, 161(1):573. DOI URL
[24]	LI Q, LIU G, CHENG H, et al. Low-temperature electrolyte design for lithium-ion batteries: prospect and challenges. Chemistry-A European Journal, 2021, 27(64):15842. DOI URL
[25]	JIAO S, REN X, CAO R, et al. Stable cycling of high-voltage lithium metal batteries in ether electrolytes. Nature Energy, 2018, 3(9):739. DOI
[26]	LIU Y, YU P, SUN Q, et al. Predicted operando polymerization at lithium anode via boron insertion. ACS Energy Letters, 2021, 6(6):2320. DOI URL
[27]	CAO W, LU J, ZHOU K, et al. Organic-inorganic composite SEI for a stable Li metal anode by in-situ polymerization. Nano Energy, 2022, 95: 106983.
[28]	CHENG S, SMITH D M, LI C Y. How does nanoscale crystalline structure affect ion transport in solid polymer electrolytes? Macromolecules, 2014, 47(12):3978. DOI URL
[29]	JOHANSSON P. First principles modelling of amorphous polymer electrolytes: Li⁺-PEO, Li⁺-PEI, and Li⁺-PES complexes. Polymer, 2001, 42(9):4367. DOI URL
[30]	SUN B, MINDEMARK J, EDSTRÖM K, et al. Polycarbonate- based solid polymer electrolytes for Li-ion batteries. Solid State Ionics, 2014, 262: 738.
[31]	SILVA M M, BARROS S C, SMITH M J, et al. Characterization of solid polymer electrolytes based on poly (trimethylenecarbonate) and lithium tetrafluoroborate. Electrochimica Acta, 2004, 49(12): 1887. DOI URL
[32]	BARBOSA P, RODRIGUES L, SILVA M M, et al. Characterization of pTMCnLiPF₆ solid polymer electrolytes. Solid State Ionics, 2011, 193(1):39. DOI URL