Thermal Runaway of Lithium-Ion Batteries without Internal Short Circuit

Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g−1 after 200 cycles at 500 mA g−1, compared to only 72% and 170 mAh g−1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials.

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“…[1] Alloy materials MM' (M = Li, Na, K; M' = Sn, Si, Sb, Ge, P, etc.) [1] Alloy materials MM' (M = Li, Na, K; M' = Sn, Si, Sb, Ge, P, etc.)…”

Section: Introductionmentioning

confidence: 99%

Boosting Superior Lithium Storage Performance of Alloy‐Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid‐Electrolyte Interphase

Xiong

Zhou

et al. 2019

Advanced Energy Materials

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“…For such purpose, people mainly focus on maximizing energy density by exploring high capacity/voltage oxide cathodes, silicon‐based anodes, and optimizing organic liquid electrolytes . However, the safety challenges related to the electrolyte are serious because operation of LIBs is exothermic and organic liquid electrolytes mostly with ester carbonates are highly flammable, generating massive heat . Dendritic lithium in LIB represents a further challenge considering internal short circuit would occur if the dendrite punctures the separator .…”

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confidence: 99%

Lithium–Graphite Paste: An Interface Compatible Anode for Solid‐State Batteries

et al. 2019

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cathodes, [10][11][12] silicon-based anodes, [13][14][15][16] and optimizing organic liquid electrolytes. [17,18] However, the safety challenges related to the electrolyte are serious because operation of LIBs is exothermic and organic liquid electrolytes mostly with ester carbonates are highly flammable, generating massive heat. [19,20] Dendritic lithium in LIB represents a further challenge considering internal short circuit would occur if the dendrite punctures the separator. [21,22] Therefore, solutions for safety of LIBs are urgently required.Inorganic ceramic solid-state electrolyte (SSE) provides an ideal alternative to liquid flammable electrolytes for the design of safe ASSBs, since ceramic SSE is nonflammable and it has adequate fracture toughness to prevent internal short circuit from lithium dendrite. [23][24][25] Furthermore, lithium metal anode, the ultimate anode with the highest specific capacity and lowest electrochemical potential has been demonstrated in ASSBs, which exhibited intrinsic safety under rigorous conditions. [26][27][28][29][30] In the search for SSEs, while most of the superionic conductors with conductivity >1 mS cm −1 are based on sulfides, such as Li 10 GeP 2 S 12 , [31,32] Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 , [33] and Li 9.6 P 3 S 12 , [34] it has shown that garnet-type oxides are the most stable SSEs with lithium metal anode. [35][36][37][38][39] However, the lithium/garnet interface appeared to have a remarkably large impedance due to the poor interfacial contact. [40] This motivates a variety of studies to turn garnet from lithiophobic to lithiophilic by coating garnet with metal, [41][42][43][44] metal oxides, [45,46] semi-conductors, [47,48] polymer interlayers, [49,50] and graphite. [51] Although these approaches have shown great progress, they mainly addressed the interface issue from garnet side. As a result, ample opportunities remain on lithium metal side.Here we introduce a new strategy to synthesize a ceramic compatible lithium anode by using graphite additives. Our scheme to implement a lithium/garnet interface experiment is sketched in Figure 1. We find that pure lithium is not compatible with garnet, which is consistent with that expected for lithiophobic garnet surface and previous reports (Figure 1a). [52] On the other side, lithium-graphite (Li-C) composite presents lower fluidity and higher viscosity compared to pure Li. So the Li-C composite, like a paste, can be casted onto garnet and exhibits an intimate contact (Figure 1b). As expected, All-solid-state batteries (ASSBs) with ceramic-based solid-state electrolytes (SSEs) enable high safety that is inaccessible with conventional lithium-ion batteries. Lithium metal, the ultimate anode with the highest specific capacity, also becomes available with nonflammable SSEs in ASSBs, which offers promising energy density. The rapid development of ASSBs, however, is significantly hampered by the large interfacial resistance as a matched lithium/ ceramic interface that is not easy to pursue. Here, a lithium-graphite...

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“…As a sharp contrast, 1 m LiDFOB/SL (Movie S1, Supporting Information) and 1 m LiDFOB/SL + 5 wt% TMSP (Figure b; Movie S2, Supporting Information) are hard to be ignited. Accelerating rate calorimetry (ARC) technology has been widely used to study the thermal (safety) properties of battery materials, single battery cell and battery pack . Herein, ARC Heat‐Wait‐Search (HWS) mode is used to reveal the superior thermal stability of 1 m LiDFOB/SL + 5 wt% TMSP than 1 m LiPF 6 carbonates‐based electrolyte (Figure c).…”

Section: Resultsmentioning

confidence: 99%

“…Conventional electrolytes process poor oxidative stability exceeding 4.5 V versus Li/Li + , leading to the undesired formation/deposition of oxidation byproducts on electrode interfaces . Moreover, the carbonate solvents are highly flammable, while the battery safety risks are rising with the improvement of energy density . Therefore, for 5 V‐class LiNi 0.5 Mn 1.5 O 4 /graphite battery, it is necessary to formulate novel electrolytes with excellent electrode compatibility, a wide electrochemical stability window, and nonflammability.…”

Section: Introductionmentioning

confidence: 99%

Deciphering the Interface of a High‐Voltage (5 V‐Class) Li‐Ion Battery Containing Additive‐Assisted Sulfolane‐Based Electrolyte

Lü

et al. 2019

Small Methods

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Next generation high energy density lithium‐ion batteries have aroused great interests worldwide. Herein, in a high‐voltage (5 V‐class) LiNi0.5Mn1.5O4/MCMB (graphitic mesocarbon microbeads) battery system using 1 m lithium difluoro(oxalate)borate/sulfolane, tris(trimethylsilyl) phosphite (TMSP) additive is added to significantly improve room/high temperature cycling performances. The unchanged X‐ray diffraction patterns suggest the bulk crystal structure of cycled MCMB anode and LiNi0.5Mn1.5O4 cathode are well preserved. Moreover, soft X‐ray absorption spectroscopy (XAS) taken from bulk sensitive fluorescence‐yield (FY) mode reveals the unchanged bulk electronic structure of cycled LiNi0.5Mn1.5O4 cathode. Therefore, it is concluded that only interface instability contributes to capacity fading of full‐cells. However, electrode/electrolyte interface and corresponding interfacial reaction processes are always “enigmatic.” First, X‐ray photoelectron spectroscopy (XPS) and in situ differential electrochemical mass spectrometry (DEMS) are used to more accurately decipher the TMSP additive action mechanism in MCMB/electrolyte interfacial reaction processes, by identifying the interfacial solid and gas byproducts, respectively. Then, the crucial role of TMSP additive in modifying cathode/electrolyte interface is revealed by XPS and soft XAS taken from surface sensitive total electron yield (TEY) mode. This paper provides valuable perspectives for formulating novel electrolytes, and for more accurately depicting additive action mechanism in “enigmatic” electrode/electrolyte interfacial reaction processes.

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Thermal Runaway of Lithium-Ion Batteries without Internal Short Circuit

Cited by 563 publications

References 43 publications

Boosting Superior Lithium Storage Performance of Alloy‐Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid‐Electrolyte Interphase

Boosting Superior Lithium Storage Performance of Alloy‐Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid‐Electrolyte Interphase

Lithium–Graphite Paste: An Interface Compatible Anode for Solid‐State Batteries

Deciphering the Interface of a High‐Voltage (5 V‐Class) Li‐Ion Battery Containing Additive‐Assisted Sulfolane‐Based Electrolyte

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