Germanium Thin Film Protected Lithium Aluminum Germanium Phosphate for Solid‐State Li Batteries

Liu, Yijie; Li, Chao; Li, Bojie; Song, Hucheng; Cheng, Zhu; Chen, Minrui; He, Ping; Zhou, Haoshen

doi:10.1002/aenm.201702374

Cited by 242 publications

(231 citation statements)

References 34 publications

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“…Solid-state synthesis Solid-state synthesis (Figure 1a)isac lassical way to prepare inorganic solid electrolytes, such as LATP and LAGP. [35,[41][42][43][44][45][46][47][48][49][50] In this method, the chemical precursorsa re mixed andball milled, followed by as olid-state reaction and densification through calcination and sintering heat treatments, which usually require high temperatures (700-1200 8C) andl ong dwell times (> 12 h). It is notable that metal oxides (i.e.,T iO 2 ,A l 2 O 3 ,G eO 2 ) are often used as precursors for conventionals olid-state synthesis.…”

Section: Synthetic Methodsmentioning

confidence: 99%

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

2019

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Inorganic solid electrolytes, in comparison with their liquid counterparts, have more potential in varioust ypes of batteries due to their dual roles of ion transportation and separation. For all-solid-state batteries, solide lectrolytes bring several advantages, [1][2][3][4][5][6] such as enhanced safety,i ncreased energy density,s olid device integration, and packaging;t hese expand the operation temperature range and potentially improve cycling stabilitya nd lifetime. Moreover,i norganic solid electrolytes are also beneficial for lithium-ion batteries and lithium-air batteries, in which they functiona se ither surface modification layers or lithium-ion conductors. [7,8] In principle, ideal solid electrolytes are expected to have several features: [9][10][11][12][13][14] 1) fast ion dynamics and negligible electronic conductivity (minimum ionic conductivity of 10 À4 Scm À1 at room temperature for practical consideration);2 )a wide electrochemical potential window for battery cycling;3 )ane xceptional mechanical strength to suppress lithium dendrite growth;4 )excellent thermal stability during the cycling processes;and 5) asimple and low cost synthetic process for large-scale applications.Generally,i norganic lithium superionic conductors are divided into three categories:o xides, sulfides, and phosphates. Suc-cessfule xamples in oxidesi nclude garnet oxides, [15,16] perovskite-type oxides, [17,18] and antiperovskite oxides. [19][20][21] Sulfide solid electrolytes include Li 2 SÀP 2 S 5 , [22,23] Li 3 PS 4 , [24][25][26] Li 7 P 3 S 11 , [27,28] Li 7 PS 6 ,a nd Li 6 PS 5 X( X = Cl, Br). [29][30][31] Popular phosphate solid electrolytes include sodium superionic conductor (NaSICON)structured lithium-ion conductors, [32][33][34][35][36] such as LiTi 2 (PO 4 ) 3 (LTP), Li 1 + x Al x Ti 2Àx (PO 4 ) 3 (LATP), and Li 1 + x Al x Ge 2Àx (PO 4 ) 3 (LAGP). Many exciting discoveries of these materials have been summarized in important review papers. [2,6,[37][38][39][40] NaSICON-type solid electrolytes, such as LATP and LAGP, have marked advantages compared with sulfides and oxides: they display chemicals tabilityi na ir and/or water,a re low cost and low toxicity,a nd have great electrochemical stability with the added benefito fe asy preparation. [2,36,38] They also exhibit attractive ionic conductivities of 10 À4 -10 À3 Scm À1 at room temperature. Such features have recently caused renewed interest in these NaSICON-structured materials and much effort has been devoted to the investigation of this type of solid electrolyte, especiallyL ATPa nd LAGP.T his manuscript reviewsr ecent progress in LATP and LAGP solid electrolytes, with as pecific focus on synthetic approaches and their effects on the crystal structures, conductive properties, and applications. Herein, general synthetic methods for LATP and LAGP solid electrolytes are first introduced, followed by ac omparison of the crystal structures, phase purities, and ionic conductivities that result from different approaches. Later,t he applications of LATP and LAGP in ful...

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Section: Synthetic Methodsmentioning

confidence: 99%

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

2019

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“…Li 1+ x Al y Ge 2− y (PO 4 ) 3 (LAGP) is presumed to be stable when in contact with Li metal, but a Ge 4+ ‐related reduction reaction was also reported . Zhou and co‐workers coated an amorphous Ge 0 thin film on an LAGP surface by sputtering. The Ge 0 thin film effectively suppressed the reduction reaction of Ge 4+ and facilitated intimate interfacial contact between the Li metal and LAGP.…”

Section: Solid‐state Electrolytesmentioning

confidence: 99%

“…[158][159][160] Li 1+x Al y Ge 2Ày (PO 4 ) 3 (LAGP) is presumed to be stable when in contact with Li metal, but aG e 4+ -related reduction reaction was also reported. [156,161] Zhou and co-workers [162] coated an amorphous Ge 0 thin film on an LAGP surface by sputtering. The Ge 0 thin film effectively suppressed the reduction reaction of Ge 4+ and facilitated intimate interfacial contact between the Li metal and LAGP.Aquasi-solid-state lithium-air battery with this Ge 0 film coated LAGP SIE was operated for 30 cycles in ambient air at acurrent density of 200 mA g À1 and discharge capacity of 1000 mAh g À1 .…”

Section: Solid Inorganic Electrolytesmentioning

confidence: 99%

Electrolytes for Rechargeable Lithium–Air Batteries

et al. 2019

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Lithium–air batteries are promising devices for electrochemical energy storage because of their ultrahigh energy density. However, it is still challenging to achieve practical Li–air batteries because of their severe capacity fading and poor rate capability. Electrolytes are the prime suspects for cell failure. In this Review, we focus on the opportunities and challenges of electrolytes for rechargeable Li–air batteries. A detailed summary of the reaction mechanisms, internal compositions, instability factors, selection criteria, and design ideas of the considered electrolytes is provided to obtain appropriate strategies to meet the battery requirements. In particular, ionic liquid (IL) electrolytes and solid‐state electrolytes show exciting opportunities to control both the high energy density and safety.

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“…On one hand, the coating layer should be compatible with Li metal. Like Al, a Ge film was sputtered onto the surface of the NASICON-type LAGP, [198] protecting Ge 4+ in the LAGP from being reduced (Figure 9e). On the other hand, the coating layer should be as thin as possible (nanometers) to decrease the migration distance of Li + ions.…”

Section: Interface Engineering To Minimize the Interfacial Resistancementioning

confidence: 99%

Section: Interface Engineering To Minimize the Interfacial Resistancementioning

confidence: 99%

Interfacial Incompatibility and Internal Stresses in All‐Solid‐State Lithium Ion Batteries

Liu

et al. 2019

Advanced Energy Materials

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The continuous depletion of fossil fuels, the increase of oil prices, and the need to decrease CO 2 emissions have stimulated intensive research on developing alternative renewable and clean energy sources. [1] Among these alternative energy sources, rechargeable Li-ion batteries (LIBs) are one of the promising candidates. To date, the LIBs basically consisting of a positive electrode (cathode), an electrolyte, and a negative electrode (anode) have widespread applications, such as portable electronic devices, pure electric vehicles (PEVs), and hybrid electric vehicles (HEVs). [2] The state-of-the-art electrolytes are usually the lithium salts (LiPF 6 , LiBF 4 , and LiCF 3 SO 3 ) dissolved in organic solvents, i.e., ethylene carbonate, propylene carbonate, polyethylene oxide, and dimethyl carbonate, [3] which exhibit excellent wetting of the electrodes and produce a fast transfer of Li + ions upon charging and discharging. However, they suffer from flammability, poor electrochemical stability, limited temperature range of operation, and low power density. [4] There is an ever-increasing demand for batteries with a higher energy and power density, although current LIBs offer volumetric and gravimetric energy densities up to 770 Wh L −1 and 260 Wh kg −1 , respectively. [5] To improve the energy/power density of LIBs, one way is to adopt high-potential cathode materials such as LiNi 0.5 Mn 1.5 O 4 (LNMO). The high-voltage plateau of LNMO (≈4.7 V vs Li/Li + ) makes its energy density 20-30% higher than the energy density of commercial LiCoO 2 and LiFePO 4 . [6] However, successful commercialization of the LNMO is restricted in high-energy LIBs due to electrolyte decomposition and side reaction of the cathodes and liquid electrolytes when operating at high voltages. [7,8] The other way to improve the energy/power density is to replace the conventional graphite anode with Li metal. The Li metal, with a low anode potential (−3.04 V vs standard hydrogen electrode) and high specific capacity (3862 mAh g −1 for the Li anode versus 372 mAh g −1 for the graphite anode), [9][10][11] has been considered as the "Holy Grail" of battery technologies. When paired with sulfur and oxygen, the theoretical energy density of Li-S (≈2567 Wh kg −1 ) and Li-O 2 (≈3505 Wh kg −1 ) batteries is far higher than the theoretical energy density of conventional LIBs (≈387 Wh kg −1 ). [12][13][14][15] When Li metal approaches the liquid electrolytes, however, unstable Li/electrolyte interface Rechargeable Li-ion batteries (LIBs) are electrochemical storage device widely applied in electric vehicles, mobile electronic devices, etc. However, traditional LIBs containing liquid electrolytes suffer from flammability, poor electrochemical stability, and limited operational temperature range. Replacement of the liquid electrolytes with inorganic solid-state electrolytes (SSEs) would solve this problem. However, several critical issues, such as poor interfacial compatibility, low ionic conductivity at ambient temperatures, etc., need to be surmounted befor...

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Germanium Thin Film Protected Lithium Aluminum Germanium Phosphate for Solid‐State Li Batteries

Cited by 242 publications

References 34 publications

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

Synthesis and Properties of NaSICON‐type LATP and LAGP Solid Electrolytes

Electrolytes for Rechargeable Lithium–Air Batteries

Interfacial Incompatibility and Internal Stresses in All‐Solid‐State Lithium Ion Batteries

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