Commercial lithium-ion (Li-ion) batteries suffer from low energy density and do not meet the growing demands of the energy storage market. Therefore, building next-generation rechargeable Li and Li-ion batteries with higher energy densities, better safety characteristics, lower cost and longer cycle life is of outmost importance. To achieve smaller and lighter next-generation rechargeable Li and Li-ion batteries that can outperform commercial Li-ion batteries, several new energy storage chemistries are being extensively studied. In this review, we summarize the current trends and provide guidelines towards achieving this goal, by addressing batteries using high-voltage cathodes, metal fluoride electrodes, chalcogen electrodes, Li metal anodes, high-capacity anodes as well as useful electrolyte solutions. We discuss the choice of active materials, practically achievable energy densities and challenges faced by the respective battery systems. Furthermore, strategies to overcome remaining challenges for achieving energy characteristics are addressed in the hope of providing a useful and balanced assessment of current status and perspectives of rechargeable Li and Li-ion batteries.

Guidelines and trends for next-generation rechargeable lithium and lithium-ion batteries.

The ever-growing demand for advanced rechargeable lithium-ion batteries in portable electronics and electric vehicles has spurred intensive research efforts over the past decade. The key to sustaining the progress in Li-ion batteries lies in the quest for safe, low-cost positive electrode (cathode) materials with desirable energy and power capabilities. One approach to boost the energy and power densities of batteries is to increase the output voltage while maintaining a high capacity, fast charge–discharge rate, and long service life. This review gives an account of the various emerging high-voltage positive electrode materials that have the potential to satisfy these requirements either in the short or long term, including nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds. The key barriers and the corresponding strategies for the practical viability of these cathode materials are discussed along with the optimization of electrolytes and other cell components, with a particular emphasis on recent advances in the literature. A concise perspective with respect to plausible strategies for future developments in the field is also provided.

High-voltage positive electrode materials for lithium-ion batteries

Since their market introduction in 1991, lithium ion batteries (LIBs) have developed evolutionary in terms of their specific energies (Wh/kg) and energy densities (Wh/L). Currently, they do not only dominate the small format battery market for portable electronic devices, but have also been successfully implemented as the technology of choice for electromobility as well as for stationary energy storage. Besides LIBs, a variety of different technologically promising battery concepts exists that, depending on the respective technology, might also be suitable for various application purposes. These systems of the “next generation,” the so-called post-lithium ion batteries (PLIBs), such as metal/sulfur, metal/air or metal/oxygen, or “post-lithium technologies” (systems without Li), which are based on alternative single (Na+, K+) or multivalent ions (Mg2+, Ca2+), are currently being studied intensively. From today’s point of view, it seems quite clear that there will not only be a single technology for all applications (technology monopoly), but different battery systems, which can be especially suitable or combined for a particular application (technology diversity). In this review, we place the lithium ion technology in a historical context and give insights into the battery technology diversity that evolved during the past decades and which will, in turn, influence future research and development.

Lithium ion, lithium metal, and alternative rechargeable battery technologies: the odyssey for high energy density

Finding a viable electrolyte for next-generation 5 V-class lithium-ion batteries is of primary importance. A long-standing obstacle has been metal-ion dissolution at high voltages. The LiPF6 salt in conventional electrolytes is chemically unstable, which accelerates transition metal dissolution of the electrode material, yet beneficially suppresses oxidative dissolution of the aluminium current collector; replacing LiPF6 with more stable lithium salts may diminish transition metal dissolution but unfortunately encounters severe aluminium oxidation. Here we report an electrolyte design that can solve this dilemma. By mixing a stable lithium salt LiN(SO2F)2 with dimethyl carbonate solvent at extremely high concentrations, we obtain an unusual liquid showing a three-dimensional network of anions and solvent molecules that coordinate strongly to Li(+) ions. This simple formulation of superconcentrated LiN(SO2F)2/dimethyl carbonate electrolyte inhibits the dissolution of both aluminium and transition metal at around 5 V, and realizes a high-voltage LiNi0.5Mn1.5O4/graphite battery that exhibits excellent cycling durability, high rate capability and enhanced safety.

/pdf/superconcentrated-electrolytes-for-a-high-voltage-lithium-5bnt0uenyd.pdf

Superconcentrated electrolytes for a high-voltage lithium-ion battery.

A solid-state high-voltage (5 V) lithium battery is demonstrated to deliver a cycle life of 10 000 with 90% capacity retention. Furthermore, the solid electrolyte enables the use of high-voltage cathodes and Li anodes with minimum side reactions, leading to a high Coulombic efficiency of 99.98+%.

Solid Electrolyte: the Key for High‐Voltage Lithium Batteries

The high-voltage LiNi0.5Mn1.5O4 (LNMO) spinel is a promising candidate for a positive electrode in lithium ion batteries, but LNMO/graphite full-cells display severe capacity fading issues due to Mn dissolution. In this study, the dissolution behaviors of Mn and Ni were examined systematically under various conditions such as state of charge (SOC), temperature, storage time, and crystal structure of LNMO. In addition, surfaces of calendar- or cycle-aged LNMO and graphite electrodes were analyzed by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), or time-of-flight secondary ion mass spectrometry (TOF-SIMS). The chemical composition of aged electrolyte was determined by gas chromatography (GC) analysis after storage of LNMO electrodes under different conditions. It was found that the amounts of dissolved Mn and Ni and diethyl ether, a decomposition product of diethyl carbonate (DEC) in electrolyte, increased with SOC, temperature, and storage time. The decomposition of electr...

Understanding Transition-Metal Dissolution Behavior in LiNi0.5Mn1.5O4 High-Voltage Spinel for Lithium Ion Batteries

The information obtained by absorbance detection when coupled with liquid chromatography is usually not specific enough to allow the qualitative ldentHication of compounds present in complex samples with any degree of certainty. With the use of mass spectrometric detection (LCIMS), characteristic mass spectral data can be obtained whkh greatly aid in eiucklating the Mentlty of unknown compounds. In this paper, ma88 spectrometric detection Is used in series with absorbance detectian to Identify or characterize antioxidants and UV light stabilizing addltives in plastic materlaIs which were separated by liquid chromatography. The two detectors were operated in series without any significant loss of chromatographic resolution. Nanogram quantities of additives could be detected by LCIMS. Lower detection limits were achieved by reconstructing mass chromatograms for selected ions. These studies demonstrate the feasibility of using LC/MS to Characterize additives In plastic materials. Chemical additives are frequently used to enhance the useful lifetime of polymeric materials. Antioxidants and ultraviolet (UV) light stabilizers are added to minimize potential polymer degradation by oxidative (1-3) or photochemical processes (3,4). Identification and quantitation of these compounds are necessary for polymer degradation studies and for quality-assurance tests. Due to the low concentration of additives in the polymer matrix (typically less than l%), a sensitive method of analysis must be employed. The high molecular weight and polarity of many antioxidants and UV light stabilizers often precludes the use of gas chromatography. High-performance liquid chromatography has been used to effectively separate these compounds (2,5-9). Identification of compounds present in real samples is based on comparison of the peaks' retention times or capacity factors (k') with those of known standards. Identification by this method not only is tedious and timeconsuming but also requires one to have all of the suspected compounds on hand so that tentative identifications can be made. Even so, erroneous identifications can often be made due to the relatively poor separating ability of HPLC (compared to capillary gas chromatography) and the chemical similarity of many compounds. The combination of liquid chromatography with mass spectrometric detection (LC/MS) can circumvent many of these problems. Many compounds, such as distearyl thiodipropionate (DSTDP), which do not absorb ultraviolet light at standard UV detection wavelengths (254 nm and 280 nm) will not be detected with a conventional UV absorbance detector. The mass spectrometer is a more universal detector. The information yielded by LC/MS greatly aids in elucidating the structure of unknown compounds. In our laboratory, ultraviolet absorbance and mass spectrometric detection were used in series to provide unique qualitative and quantitative information on plastic additives separated by liquid chromatography. Additional peak 0003-2700/85/0357-0672$01.50/0 broadening introduced by this detection arrangement was minimal. The system was used to characterize the additives present in several polymeric samples.

Identification of antioxidant and ultraviolet light stabilizing additives in plastics by liquid chromatography/mass spectrometry

Determination of aldehydes and ketones by derivatization and liquid chromatography—mass spectrometry

A photocatalytic HC/SCR system has been developed and its high deNOx performance (54.0–98.6% NOx conversion) at low temperatures (150–250 °C) demonstrated by using a representative diesel fuel hydrocarbon (dodecane) as the reductant over a hybrid SCR system of a photocatalytic reactor (PCR) and a dual-bed HC/SCR reactor. The PCR generates highly active oxidants such as O3 and NO2 from O2 and NO in the feed stream, followed by the subsequent formation of highly efficient reductants such as oxygenated hydrocarbon (OHC), NH3, and organo-nitrogen compounds. These reductants are the key components for enhancing the low temperature deNOx performance of the dual-bed HC/SCR system containing Ag/Al2O3 and CuCoY in the front and rear bed of the reactor, respectively. The OHCs are particularly effective for both NOx reduction and NH3 formation over the Ag/Al2O3 catalyst, while NH3 and organo-nitrogen compounds are effective for NOx reduction over the CuCoY catalyst. The hybrid HC/SCR system assisted by photocatalysi...

Keith L. Olson

Papers

Understanding Transition-Metal Dissolution Behavior in LiNi0.5Mn1.5O4 High-Voltage Spinel for Lithium Ion Batteries

Identification of antioxidant and ultraviolet light stabilizing additives in plastics by liquid chromatography/mass spectrometry

Determination of aldehydes and ketones by derivatization and liquid chromatography—mass spectrometry

Combination of Photocatalysis and HC/SCR for Improved Activity and Durability of DeNOx Catalysts

Characterization of additives in plastics by liquid chromatography-mass spectrometry