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Abstract: Solid electrolytes represent a critical component in future batteries that provide higher energy and power densities than the current lithium‐ion batteries. The potential of using ultrathin films is among the best merits of solid electrolytes for considerably reducing the weight and volume of each battery unit, thereby significantly enhancing the energy density. However, it is challenging to fabricate ultrathin membranes of solid electrolytes using the conventional techniques. Here, a new strategy is reported for fabricating sub‐micrometer‐thick membranes of β‐Li3PS4 solid electrolytes via tiled assembly of shape‐controlled, nanoscale building blocks. This strategy relies on facile, low‐cost, solution‐based chemistry to create membranes with tunable thicknesses. The ultrathin membranes of β‐Li3PS4 show desirable ionic conductivity and necessary compatibility with metallic lithium anodes. The results of this study also highlight a viable strategy for creating ultrathin, dense solid electrolytes with high ionic conductivities for the next‐generation energy storage and conversion systems. [ABSTRACT FROM AUTHOR]

Abstract: Nickel‐rich layered oxide cathodes with the composition LiNi1−x−yCoxMnyO2 (NCM, (1−x−y) ≥ 0.6) are under intense scrutiny recently to contend with commercial LiNi0.8Co0.15Al0.05O2 (NCA) for high‐energy‐density batteries for electric vehicles. However, a comprehensive assessment of their electrochemical durability is currently lacking. Herein, two in‐house cathodes, LiNi0.8Co0.15Al0.05O2 and LiNi0.7Co0.15Mn0.15O2, are investigated in a high‐voltage graphite full cell over 1500 charge‐discharge cycles (≈5–10 year service life in vehicles). Despite a lower nickel content, NCM shows more performance deterioration than NCA. Critical underlying degradation processes, including chemical, structural, and mechanical aspects, are analyzed via an arsenal of characterization techniques. Overall, Mn substitution appears far less effective than Al in suppressing active mass dissolution and irreversible phase transitions of the layered oxide cathodes. The active mass dissolution (and crossover) accelerates capacity decline with sustained parasitic reactions on the graphite anode, while the phase transitions are primarily responsible for cell resistance increase and voltage fade. With Al doping, on the other hand, secondary particle pulverization is the more limiting factor for long‐term cyclability compared to Mn. These results establish a fundamental guideline for designing high‐performing Ni‐rich NCM cathodes as a compelling alternative to NCA and other compositions for electric vehicle applications. [ABSTRACT FROM AUTHOR]

A novel battery hybrid composite anode consisting of tin nanoparticles encapsulated by double nets of carbon matrixes is presented. The improved electron transfer and volume change accommodation are confirmed via density functional theory modeling and in situ transmission electron microscopy observations, respectively. [ABSTRACT FROM AUTHOR]

Li-ion-conducting solid electrolytes can simultaneously overcome two grand challenges for Li-ion batteries: the severe safety concerns that limit the large-scale application and the poor electrolyte stability that forbids the use of high-voltage cathodes. Nevertheless, the ionic conductivity of solid electrolytes is typically low, compromising the battery performances. Precisely determining the ionic transport mechanism(s) is a prerequisite for the rational design of highly conductive solid electrolytes. For decades, the research on this subject has primarily focused on the atomic and microscopic scales, where the main features of interest are unit cells and microstructures, respectively. Here, it is shown that the largely overlooked mesoscopic scale lying between these extremes could be the key to fast ionic conduction. In a prototype system, (Li0.33La0.56)TiO3, a mesoscopic framework is revealed for the first time by state-of-the-art scanning transmission electron microscopy. Corroborated by theoretical calculations and impedance measurements, it is demonstrated that such a unique configuration maximizes the number of percolation directions and thus most effectively improves the ionic conductivity. This discovery reconciles the long-standing structure-property inconsistency in (Li0.33La0.56)TiO3 and also identifies mesoscopic ordering as a promising general strategy for optimizing Li+ conduction. [ABSTRACT FROM AUTHOR]

The increasing demand for a safe rechargeable battery with a high energy density per cell is driving a search for a novel solid electrolyte with a high Li or Na conductivity that is chemically stable in a working Li-ion or Na-ion battery. LiZnNbO (LZNO) has been reported to exhibit a σ > 10 S cm at 250 °C, but to disproportionate into multiple phases on cooling from 850 °C to room-temperature. An investigation of the room-temperature Li-ion conductivity in a porous pellet of a multiphase product of a nominal LZNO composition is shown to have bulk σ ≈ 3.3 × 10 S cm at room-temperature that increases to 1.4 × 10 S cm by 50 °C. Li MAS NMR spectra were fitted to two Lorentzian lines, one of which showed a dramatic increase with increasing temperature. A test for water stability indicates that Li may move to the particle and grain surfaces to react with adsorbed water as occurs in the garnet Li conductors. [ABSTRACT FROM AUTHOR]

A solid‐state high‐voltage (5 V) lithium battery is demonstrated to deliver a cycle life of 10 000 with 90% capacity retention. 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+%. [ABSTRACT FROM AUTHOR]

Batteries with an aqueous catholyte and a Li metal anode have attracted interest owing to their exceptional energy density and high charge/discharge rate. The long-term operation of such batteries requires that the solid electrolyte separator between the anode and aqueous solutions must be compatible with Li and stable over a wide pH range. Unfortunately, no such compound has yet been reported. In this study, an excellent stability in neutral and strongly basic solutions was observed when using the cubic Li7La3Zr2O12 garnet as a Li-stable solid electrolyte. The material underwent a Li+/H+ exchange in aqueous solutions. Nevertheless, its structure remained unchanged even under a high exchange rate of 63.6 %. When treated with a 2 M LiOH solution, the Li+/H+ exchange was reversed without any structural change. These observations suggest that cubic Li7La3Zr2O12 is a promising candidate for the separator in aqueous lithium batteries. [ABSTRACT FROM AUTHOR]

High‐voltage (5 volt) lithium‐ion chemistry is realized with Lipon, a glass solid electrolyte. In article number 1401408, Juchuan Li, Nancy J. Dudney, and co‐workers describe the battery, which consists of a LiNi0.5Mn1.5O4 spinel cathode and a lithium metal anode. This solid‐state battery delivers a high coulombic efficiency of >99.98% and stable cycling of >90% retention for 10 000 cycles. [ABSTRACT FROM AUTHOR]

Recent calculations and experimentaldata suggest that understandingthe local ordering behavior of Ni/Mn will be critical to optimizethe electrochemical properties of LiNi0.5Mn1.5O4(LNMO) high voltage spinel. In this study, we systematicallycontrolled the evolution of Ni and Mn ordering in LNMO samples byannealing them at 700 °C in air for different dwelling times,followed by quenching to room temperature. The long- and short-rangeordering behavior of Ni and Mn were analyzed by combining neutronpowder diffraction, X-ray powder diffraction (XRD), transmission electronmicroscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR)data. The results show that the fraction of ordered phase increasesrapidly during initial annealing at 700 °C for 6 h, and accompaniedby decreasing amounts of secondary phases. Annealing longer than 6h led to the growth in size of ordered domains (i.e., increased segregationof ordered and disordered domains) along with a slow increase in thefraction of ordered phase. The dependence of open circuit voltages(OCVs) of the LNMO on the degree of ordering agrees well with recentcalculations using the density functional theory. The increase inthe degree of ordering increases the open circuit voltage (OCV) andthe initial capacity but reduces cycle life and rate capability. TheLNMO delivered optimal battery performances (capacity, cycle life,and rate capability) after annealing at 700 °C for 2 h. Thispartially ordered sample showed the respective advantages from bothdisordered and ordered spinels: better spinel-phase purity (thus,higher initial capacity) from the ordered LNMO and better cycle lifeand rate capability from the disordered LNMO. [ABSTRACT FROM AUTHOR]

Hollow nanostructures have received broad attention for lithium-storage owing to their advantages in accommodating volume-change. However, taking the hollow sphere as an example, the void inside consumes a large volume fraction, resulting in a low material loading. Herein, we present a novel hollow nanosheet using Co 2 SiO 4 as demonstrating example. The Co 2 SiO 4 nanosheets-based anode exhibits a high and stable capacity of 1456 mAh g−1 after 200 cycles at 0.2 A g−1, and an excellent rate-performance after three rounds of cycling. In addition, the dynamic lithiation and delithiation of Co 2 SiO 4 are presented using an in situ transmission electron microscopy technology. Unlabelled Image • A novel hollow Co 2 SiO 4 nanosheet secondary battery anode is presented. • Excellent electrochemical performance with stable capacity and high rate-performance is achievable. • Dynamic lithiation/delithiation is demonstrated using in situ transmission electron microscopy. [ABSTRACT FROM AUTHOR]

Abstract: Self-organized amorphous TiO2 nanotube arrays (NTAs) were successfully fabricated on both Ti foil and porous Ti foam through electrochemical anodization techniques. The starting Ti foams were fabricated using ARCAM''s Electron Beam Melting (EBM) technology. The TiO2 NTAs on Ti foam were used as anodes in lithium ion batteries; they exhibited high capacities of 103 μAh cm−2 at 10 μA cm−2 and 83 μAh cm−2 at 500 μA cm−2, which are two to three times higher than those achieved on the standard Ti foil, which is around 40 μAh cm−2 at 10 μA cm−2 and 24 μAh cm−2 at 500 μA cm−2, respectively. This improvement is mainly attributed to higher surface area of the Ti foam and higher porosity of the nanotube arrays layer grown on the Ti foam. In addition, a Na-ion half-cell composed of these NTAs anodes and Na metal as the counter electrode showed a self-improved specific capacity upon cycling at 10 μA cm−2. These results indicate that TiO2 NTAs grown on Ti porous foam are promising electrodes for Li-ion or Na-ion rechargeable batteries. [Copyright &y& Elsevier]

Abstract: Silicon nanowires (NWs) have been reported as a promising anode that demonstrated high capacity without pulverization during cycling, however, they present some technical issues that remain to be solved. The high aspect ratio of the NWs and their small contact areas with the current collector cause high electrical resistance, which results in inefficient electron transport. The nano-size interface between a NW and the substrate experiences high shear stress during lithiation, causing the wire to separate from the current collector. In addition, most reported methods for producing silicon NWs involve high-temperature processing and require catalysts that later become contaminants. This study developed a new self-aligned Cu–Si core–shell NW array using a low-temperature, catalyst-free process to address the issues described. The silicon shell is amorphous as synthesized and accommodates Li-ions without phase transformation. The copper core functions as a built-in current collector to provide very short (nm) electron transport pathways as well as backbone to improve mechanical strength. Initial electrochemical evaluation has demonstrated good capacity retention and high Coulombic efficiency for this new anode material in a half-cell configuration. No wire fracture or core–shell separation was observed after cycling. However, electrolyte decomposition products largely covered the top surface of the NW array, restricting electrolyte access and causing capacity reduction at high charging rates. [Copyright &y& Elsevier]

Abstract: For high-voltage cycling of rechargeable Li batteries, a nano-scale amorphous Li-ion conductor, lithium phosphorus oxynitride (Lipon), has been coated on surfaces of LiCoO2 particles by combining a RF-magnetron sputtering technique and mechanical agitation of LiCoO2 powders. LiCoO2 particles coated with 0.36wt% (∼1nm thick) of the amorphous Lipon, retain 90% of their original capacity compared to non-coated cathode materials that retain only 65% of their original capacity after more than 40 cycles in the 3.0–4.4V range with a standard carbonate electrolyte. The reason for the better high-voltage cycling behavior is attributed to reduction in the side reactions that cause increase of the cell resistance during cycling. Further, Lipon coated particles are not damaged, whereas uncoated particles are badly cracked after cycling. Extending the charge of Lipon-coated LiCoO2 to higher voltage enhances the specific capacity, but more importantly the Lipon-coated material is also more stable and tolerant of high voltage excursions. A drawback of Lipon coating, particularly as thicker films are applied to cathode powders, is the increased electronic resistance that reduces the power performance. [Copyright &y& Elsevier]