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Journal ArticleDOI

Review—SEI: Past, Present and Future

01 Jan 2017-Journal of The Electrochemical Society (The Electrochemical Society)-Vol. 164, Iss: 7
About: This article is published in Journal of The Electrochemical Society.The article was published on 2017-01-01. It has received 1199 citations till now.
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Journal ArticleDOI
TL;DR: In this article, the authors discuss the challenges and future research directions towards fast charging at the level of battery materials from mass transport, charge transfer and thermal management perspectives, and highlight advanced characterization techniques to understand the failure mechanisms of batteries during fast charging, which in turn would inform more rational battery designs.
Abstract: Extreme fast charging, with a goal of 15 minutes recharge time, is poised to accelerate mass market adoption of electric vehicles, curb greenhouse gas emissions and, in turn, provide nations with greater energy security. However, the realization of such a goal requires research and development across multiple levels, with battery technology being a key technical barrier. The present-day high-energy lithium-ion batteries with graphite anodes and transition metal oxide cathodes in liquid electrolytes are unable to achieve the fast-charging goal without negatively affecting electrochemical performance and safety. Here we discuss the challenges and future research directions towards fast charging at the level of battery materials from mass transport, charge transfer and thermal management perspectives. Moreover, we highlight advanced characterization techniques to fundamentally understand the failure mechanisms of batteries during fast charging, which in turn would inform more rational battery designs. Along with high energy density, fast-charging ability would enable battery-powered electric vehicles. Here Yi Cui and colleagues review battery materials requirements for fast charging and discuss future design strategies.

866 citations

Journal ArticleDOI
TL;DR: The complexity of multivalent metal-ion chemistries has led to rampant confusions, technical challenges, and eventually doubts and uncertainties about the future of these technologies as discussed by the authors, leading to rampant confusion and technical challenges.
Abstract: Batteries based on multivalent metals have the potential to meet the future needs of large-scale energy storage, due to the relatively high abundance of elements such as magnesium, calcium, aluminium and zinc in the Earth’s crust. However, the complexity of multivalent metal-ion chemistries has led to rampant confusions, technical challenges, and eventually doubts and uncertainties about the future of these technologies. In this Review, we clarify the key strengths as well as common misconceptions of multivalent metal-based batteries. We then examine the growth behaviour of metal anodes, which is crucial for their safety promises but hitherto unestablished. We further discuss scrutiny of anode efficiency and cathode storage mechanism pertaining to complications arising from electrolyte solutions. Finally, we critically review existing cathode materials and discuss design strategies to enable genuine multivalent metal-ion-based energy storage materials with competitive performance. Batteries based on multivalent metal anodes hold great promise for large-scale energy storage but their development is still at an early stage. This Review surveys the main complexity arising from anodes, electrolytes and cathodes, and offers views on the progression path of these technologies.

590 citations

Journal ArticleDOI
TL;DR: The distinctive features of the typical interfaces and interphases in ASSBs are presented and the recent work on identifying, probing, understanding, and engineering them are summarized.
Abstract: All-solid-state batteries (ASSBs) have attracted enormous attention as one of the critical future technologies for safe and high energy batteries. With the emergence of several highly conductive solid electrolytes in recent years, the bottleneck is no longer Li-ion diffusion within the electrolyte. Instead, many ASSBs are limited by their low Coulombic efficiency, poor power performance, and short cycling life due to the high resistance at the interfaces within ASSBs. Because of the diverse chemical/physical/mechanical properties of various solid components in ASSBs as well as the nature of solid-solid contact, many types of interfaces are present in ASSBs. These include loose physical contact, grain boundaries, and chemical and electrochemical reactions to name a few. All of these contribute to increasing resistance at the interface. Here, we present the distinctive features of the typical interfaces and interphases in ASSBs and summarize the recent work on identifying, probing, understanding, and engineering them. We highlight the complicated, but important, characteristics of interphases, namely the composition, distribution, and electronic and ionic properties of the cathode-electrolyte and electrolyte-anode interfaces; understanding these properties is the key to designing a stable interface. In addition, conformal coatings to prevent side reactions and their selection criteria are reviewed. We emphasize the significant role of the mechanical behavior of the interfaces as well as the mechanical properties of all ASSB components, especially when the soft Li metal anode is used under constant stack pressure. Finally, we provide full-scale (energy, spatial, and temporal) characterization methods to explore, diagnose, and understand the dynamic and buried interfaces and interphases. Thorough and in-depth understanding on the complex interfaces and interphases is essential to make a practical high-energy ASSB.

538 citations

Journal ArticleDOI
TL;DR: In this article, a fluorinated orthoformate-based electrolyte was used to prevent dendritic Li formation and minimise Li loss and volumetric expansion in Li-metal batteries.
Abstract: Lithium (Li) pulverization and associated large volume expansion during cycling is one of the most critical barriers for the safe operation of Li-metal batteries. Here, we report an approach to minimize the Li pulverization using an electrolyte based on a fluorinated orthoformate solvent. The solid–electrolyte interphase (SEI) formed in this electrolyte clearly exhibits a monolithic feature, which is in sharp contrast with the widely reported mosaic- or multilayer-type SEIs that are not homogeneous and could lead to uneven Li stripping/plating and fast Li and electrolyte depletion over cycling. The highly homogeneous and amorphous SEI not only prevents dendritic Li formation, but also minimizes Li loss and volumetric expansion. Furthermore, this new electrolyte strongly suppresses the phase transformation of the LiNi0.8Co0.1Mn0.1O2 cathode (from layered structure to rock salt) and stabilizes its structure. Tests of high-voltage Li||NMC811 cells show long-term cycling stability and high rate capability, as well as reduced safety concerns. Parasitic reactions between Li metal and electrolytes need to be mitigated in Li-metal batteries. Here, the authors report the use of a fluorinated orthoformate-based electrolyte, leading to a monolithic solid–electrolyte interphase and subsequently a high-performance Li-metal battery.

512 citations

Journal ArticleDOI
TL;DR: A molecular-level SEI design using a reactive polymer composite is shown to effectively construct a stable SEI layer and suppress electrolyte consumption upon cycling, which effectively suppresses electrolytes consumption in the formation and maintenance of the SEI.
Abstract: The solid–electrolyte interphase (SEI) is pivotal in stabilizing lithium metal anodes for rechargeable batteries. However, the SEI is constantly reforming and consuming electrolyte with cycling. The rational design of a stable SEI is plagued by the failure to control its structure and stability. Here we report a molecular-level SEI design using a reactive polymer composite, which effectively suppresses electrolyte consumption in the formation and maintenance of the SEI. The SEI layer consists of a polymeric lithium salt, lithium fluoride nanoparticles and graphene oxide sheets, as evidenced by cryo-transmission electron microscopy, atomic force microscopy and surface-sensitive spectroscopies. This structure is different from that of a conventional electrolyte-derived SEI and has excellent passivation properties, homogeneity and mechanical strength. The use of the polymer–inorganic SEI enables high-efficiency Li deposition and stable cycling of 4 V Li|LiNi0.5Co0.2Mn0.3O2 cells under lean electrolyte, limited Li excess and high capacity conditions. The same approach was also applied to design stable SEI layers for sodium and zinc anodes. Solid–electrolyte interphase is crucial for stabilizing lithium metal anodes for rechargeable batteries. A molecular-level design using a reactive polymer composite is now shown to effectively construct a stable SEI layer and suppress electrolyte consumption upon cycling.

493 citations

References
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Journal ArticleDOI
TL;DR: In this article, the rate constants for over 3500 reaction are tabulated, including reaction with molecules, ions and other radicals derived from inorganic and organic solutes, and the corresponding radical anions, ⋅O− and eaq−, have been critically pulse radiolysis, flash photolysis and other methods.
Abstract: Kinetic data for the radicals H⋅ and ⋅OH in aqueous solution,and the corresponding radical anions, ⋅O− and eaq−, have been critically pulse radiolysis, flash photolysis and other methods. Rate constants for over 3500 reaction are tabulated, including reaction with molecules, ions and other radicals derived from inorganic and organic solutes.

9,887 citations

Journal ArticleDOI
TL;DR: In this article, the mechanisms of lithium-ion battery ageing are reviewed and evaluated, and the most promising candidate as the power source for (hybrid) electric vehicles and stationary energy storage.

3,115 citations

Journal ArticleDOI
01 Jul 1998-Nature
TL;DR: In this article, the authors showed that nanometre-sized ceramic powders can be used as solid plasticizers for polyethylene oxide (PEO) electrolytes to prevent crystallization on annealing from amorphous state above 60°C.
Abstract: Ionically conducting polymer membranes (polymer electrolytes) might enhance lithium-battery technology by replacing the liquid electrolyte currently in use and thereby enabling the fabrication of flexible, compact, laminated solid-state structures free from leaks and available in varied geometries1. Polymer electrolytes explored for these purposes are commonly complexes of a lithium salt (LiX) with a high-molecular-weight polymer such as polyethylene oxide (PEO). But PEO tends to crystallize below 60 °C, whereas fast ion transport is a characteristic of the amorphous phase. So the conductivity of PEO–LiX electrolytes reaches practically useful values (of about 10−4 S cm−1) only at temperatures of 60–80 °C. The most common approach for lowering the operational temperature has been to add liquid plasticizers, but this promotes deterioration of the electrolyte's mechanical properties and increases its reactivity towards the lithium metal anode. Here we show that nanometre-sized ceramic powders can perform as solid plasticizers for PEO, kinetically inhibiting crystallization on annealing from the amorphous state above 60 °C. We demonstrate conductivities of around 10−4 S cm−1 at 50 °C and 10−5 S cm−1 at 30 °C in a PEO–LiClO4 mixture containing powders of TiO2 and Al2O3 with particle sizes of 5.8–13 nm. Further optimization might lead to practical solid-state polymer electrolytes for lithium batteries.

2,695 citations

Journal ArticleDOI
TL;DR: The solid electrolyte interphase (SEI) is a protecting layer formed on the negative electrode of Li-ion batteries as a result of electrolyte decomposition, mainly during the first cycle as discussed by the authors.

2,386 citations