Recent advances in the electrolytes for interfacial stability of high-voltage cathodes in lithium-ion batteries
TL;DR: In this article, the authors describe several challenges for the cathode (spinel lithium manganese oxide (LMO), lithium cobalt oxide (LCO), lithium nickel cobalt manganes oxide (NCM), spinel lithium ion ion oxide (SILO), and lithium-rich layered oxide (Li-rich cathode))-electrolyte interfaces and highlight the recent progress in the use of oxidative additives and highvoltage solvents in high-performance cells.
Abstract: Advanced electrolytes with unique functions such as in situ formation of a stable artificial solid electrolyte interphase (SEI) layer on the anode and the cathode, and the improvement in oxidation stability of the electrolyte have recently gained recognition as a promising means for highly reliable lithium-ion batteries with high energy density. In this review, we describe several challenges for the cathode (spinel lithium manganese oxide (LMO), lithium cobalt oxide (LCO), lithium nickel cobalt manganese oxide (NCM), spinel lithium manganese nickel oxide (LNMO), and lithium-rich layered oxide (Li-rich cathode))-electrolyte interfaces and highlight the recent progress in the use of oxidative additives and high-voltage solvents in high-performance cells.
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TL;DR: In this paper, an enlarged crystal cell mechanism was proposed to increase the discharge capacity and initial coulombic efficiency of Li ion batteries, which achieved an improved high energy capacity of 308 mAhg−1 and an initial coulcombic capacity of 85%.
47 citations
01 Jan 2017
TL;DR: LiDFBP-derived SEI layer effectively suppresses severe electrolyte decomposition at high voltages and mitigates the voltage decay of the lithium-rich cathodes caused by undesirable phase transformation to spinel-like phases during cycling as discussed by the authors.
Abstract: Lithium difluoro(bisoxalato)phosphate (LiDFBP) is introduced as a novel lithium-salt-type electrolyte additive for lithium-rich cathodes in lithium-ion batteries. The investigation reveals that LiDFBP is oxidized to form a uniform and electrochemically stable solid electrolyte interphase (SEI) on the lithium-rich cathode. The LiDFBP-derived SEI layer effectively suppresses severe electrolyte decomposition at high voltages and mitigates the voltage decay of the lithium-rich cathodes caused by undesirable phase transformation to spinel-like phases during cycling. Furthermore, the cell with electrolyte containing LiDFBP achieves substantially improved cycling performance and delivers a high discharge capacity of 116 mA h g−1 at a high C rate (20 C). The unique function of the LiDFBP additive on the surface chemistry of lithium-rich cathodes is confirmed through X-ray photoelectron spectroscopy, SEM, and TEM analyses.
46 citations
TL;DR: A review of electrolyte design for battery interphases can be found in this article , where Meng et al. discuss progress in designing better electrolytes for electrochemical devices and how to tailor them using electrolyte engineering.
Abstract: Electrolytes and the associated interphases constitute the critical components to support the emerging battery chemistries that promise tantalizing energy but involve drastic phase and structure complications. Designing better electrolytes and interphases holds the key to the success of these batteries. As the only component that interfaces with every other component in the device, an electrolyte must satisfy multiple criteria simultaneously. These include transporting ions while insulating electrons between the electrodes and maintaining stability against electrodes of extreme chemical natures: the strongly oxidative cathode and the strongly reductive anode. In most advanced batteries, the two electrodes operate at potentials far beyond the thermodynamic stability limits of electrolytes, so the stability therein has to be realized kinetically through an interphase formed from the sacrificial reactions between electrolyte and electrodes. Description Progress and challenges for electrolytes Compared with the development of new cathodes and anodes, there has been less of a focus on the development of electrolytes. However, it is the electrolyte that controls the flow of ions and charges, and it is the only component in intimate contact with all the others. With the push toward higher energy and power densities, electrolytes are also involved in kinetically formed interphases that aid in the stability of a battery but can also hamper its operation. In a review, Meng et al. captures a number of trends that have emerged in the development of advanced battery electrolytes. —MSL A review discusses progress in designing better electrolytes for electrochemical devices. BACKGROUND The electrolyte is an indispensable component in every electrochemical device, including lithium-ion batteries (LIBs). It physically segregates two electrodes from direct electron transfer while allowing working ions to transport both charges and masses across the cell so that the cell reactions can proceed sustainably. Whether powering our phones, driving our vehicles, or harvesting the intermittent energy from solar and wind farms, electrolytes in these LIBs determine how fast and how many times our devices can be recharged or how efficiently energy can be captured and stored over the grid. Occasionally, when an LIB is pushed away from the designed electrochemistry pathways by various factors such as excessive heat, mechanical mutilation, or internal short circuits induced under extreme charging conditions, electrolytes are also responsible for the fire and explosion accidents that we read about in the news. The electrolyte is the most unique component in a battery. Because it must physically interface with every other component, it is obligated to satisfy numerous constraints simultaneously, including rapidly transporting ions and masses, effectively insulating electrons, and maintaining stability toward the strongly oxidative cathode and strongly reductive anode. Historically, the electrolyte-anode interfacing was the last piece of the puzzle to complete modern LIB chemistry. ADVANCES The commercial success of LIBs has attracted intense interest and investments in electrolyte research, which led to the identification of interphases as the key component responsible for the stable and reversible operations of cathode and anode materials far beyond the thermodynamic stability limits of any known electrolyte. These interphases, often with nanometer thickness, are formed by electrolytes in a self-limiting decomposition process, and they ensure fast rates of charging and discharging, maximum voltage, and reversibility of LIBs. In the past three decades, the chemistry, morphology, and formation mechanisms of interphases have been thoroughly investigated. Researchers have learned how such interphases are structured and what key ingredients they comprise and, most importantly, how to tailor them using electrolyte engineering. Today, it is widely accepted that designing better electrolytes also implies designing the associated interphases for the electrode materials. Although the accurate prediction of interphasial chemistry remains difficult, and key fundamental properties of interphases such as the rate and mechanism of ion transport across interphases are still unknown, the structure of the ion solvation sheath has been identified as an effective tool that directs the formation process of interphases. Such knowledge has been driving a series of new electrolyte concepts for emerging battery chemistries. OUTLOOK Efforts are being made to develop battery chemistries that promise high energy density, rapid charging, low cost, high sustainability, and independence from elements or materials of high geopolitical or ethical risks. Each individual chemistry may demand a unique electrolyte and corresponding interphase, but a few universal trends emerge: (i) a super-concentration of salts is used to leverage unusual properties arising from the altered ion-solvation structures; (ii) both polymeric and inorganic materials are used to solidify electrolytes so that the aggressive lithium-metal anode can be harnessed with higher safety; (iii) efforts are made to identify the most effective interphasial ingredients so that an interphase of singular composition can be designed and artificially applied; (iv) liquefied gaseous components are used to expand the low-temperature limits of conventional electrolytes; and (v) unusual electrochemical behaviors are explored by confining ion-solvation sheaths in nano- or sub-nano environments. Electrolytes and the associated interphases play the central role in supporting diversified battery chemistries. On the anode side (left), the electrolyte must form an interphase that prevents graphitic anode from exfoliation, tolerates the drastic volume changes of a silicon electrode, and suppresses the growth of a dendritic form of lithium metal. On the cathode side (right), an interphase is critical in preventing the irreversible reactions with electrolytes, maintaining the lattice structure of transition metal oxides, suppressing the cross-cell shuttling of polysulfide species, and assisting the complicated triphasial reactions of an air-cathode. In all of these scenarios, interphases must enable ionic transport while insulating electronic transport.
46 citations
TL;DR: In this article, 3-methyl-1,4,2-dioxazol-5-one (MDO) is synthesized and investigated as new highly effective SEI-forming electrolyte additive which can sufficiently suppress electrolyte reduction and graphite exfoliation in propylene carbonate (PC)-based electrolytes.
Abstract: The electrochemical and thermal stabilities of commonly used LiPF6/organic carbonate-based electrolytes are still a bottleneck for the development of high energy density lithium-ion batteries (LIBs) operating at elevated cell voltage and elevated temperature. The use of intrinsic electrochemically stable electrolyte solvents, e.g. sulfones or dinitriles, has been reported as one approach to enable high voltage LIBs. However, the major challenge of these solvents is related to their poor reductive stability and lack of solid electrolyte interphase (SEI)-forming ability on the graphite electrode. Here, 3-methyl-1,4,2-dioxazol-5-one (MDO) is synthesized and investigated as new highly effective SEI-forming electrolyte additive which can sufficiently suppress electrolyte reduction and graphite exfoliation in propylene carbonate (PC)-based electrolytes. With the addition of only 2 wt % MDO, LiNi0.5Mn0.3Co0.2O2 (NMC532)/graphite full cells containing a 1 M LiPF6 in PC electrolyte reach a cycle life of more than ...
45 citations
44 citations
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TL;DR: A brief historical review of the development of lithium-based rechargeable batteries is presented, ongoing research strategies are highlighted, and the challenges that remain regarding the synthesis, characterization, electrochemical performance and safety of these systems are discussed.
Abstract: Technological improvements in rechargeable solid-state batteries are being driven by an ever-increasing demand for portable electronic devices. Lithium-ion batteries are the systems of choice, offering high energy density, flexible and lightweight design, and longer lifespan than comparable battery technologies. We present a brief historical review of the development of lithium-based rechargeable batteries, highlight ongoing research strategies, and discuss the challenges that remain regarding the synthesis, characterization, electrochemical performance and safety of these systems.
17,496 citations
TL;DR: The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.
Abstract: The increasing interest in energy storage for the grid can be attributed to multiple factors, including the capital costs of managing peak demands, the investments needed for grid reliability, and the integration of renewable energy sources. Although existing energy storage is dominated by pumped hydroelectric, there is the recognition that battery systems can offer a number of high-value opportunities, provided that lower costs can be obtained. The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.
11,144 citations
TL;DR: The energy that can be stored in Li-air and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed.
Abstract: Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.
7,895 citations
TL;DR: The phytochemical properties of Lithium Hexafluoroarsenate and its Derivatives are as follows: 2.2.1.
Abstract: 2.1. Solvents 4307 2.1.1. Propylene Carbonate (PC) 4308 2.1.2. Ethers 4308 2.1.3. Ethylene Carbonate (EC) 4309 2.1.4. Linear Dialkyl Carbonates 4310 2.2. Lithium Salts 4310 2.2.1. Lithium Perchlorate (LiClO4) 4311 2.2.2. Lithium Hexafluoroarsenate (LiAsF6) 4312 2.2.3. Lithium Tetrafluoroborate (LiBF4) 4312 2.2.4. Lithium Trifluoromethanesulfonate (LiTf) 4312 2.2.5. Lithium Bis(trifluoromethanesulfonyl)imide (LiIm) and Its Derivatives 4313
5,710 citations
TL;DR: The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors.
Abstract: Energy-storage technologies, including electrical double-layer capacitors and rechargeable batteries, have attracted significant attention for applications in portable electronic devices, electric vehicles, bulk electricity storage at power stations, and “load leveling” of renewable sources, such as solar energy and wind power. Transforming lithium batteries and electric double-layer capacitors requires a step change in the science underpinning these devices, including the discovery of new materials, new electrochemistry, and an increased understanding of the processes on which the devices depend. The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors.
2,412 citations