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All-inorganic solid-state batteries (SSBs) currently attract much attention as next-generation high-density energy-storage technology. However, to make SSBs competitive with conventional Li-ion batteries, several obstacles and challenges must be overcome, many of which are related to interface stability issues. Protective coatings can be applied to the electrode materials to mitigate side reactions with the solid electrolyte, with lithium transition metal oxides, such as LiNbO3 or Li2ZrO3, being well established in research. In addition, it has been recognized lately that carbonates incorporated into the coating may also positively affect the interface stability. In this work, we studied the effect that surface carbonates in case of Li2ZrO3-coated Li1+x(Ni0.6Co0.2Mn0.2)1-xO2 (NCM622) cathode material have on the cyclability of pellet stack SSB cells with Li6PS5Cl and Li4Ti5O12 as a solid electrolyte and an anode, respectively. Both carbonate-rich and carbonate-poor hybrid coatings were produced by altering the synthesis conditions. The best cycling performance was achieved for carbonate-deficient Li2ZrO3-coated NCM622 due to decreased degradation of the argyrodite solid electrolyte at the interfaces, as determined by ex situ X-ray photoelectron spectroscopy and in situ differential electrochemical mass spectrometry. The results emphasize the importance of tailoring the composition and nature of protective coatings to improve the cyclability of bulk SSBs.

The Li–Ni–O phase diagram contains a variety of compounds, most of which are electrochemically active in Li-ion batteries. Other than the well-known LiNiO2, here we report a facile solid-state meth...

Lithium-excess disordered rock-salt oxides have opened up a new vista in search of high-capacity cathodes, resulting in a variety of new materials with versatile elemental compositions. This work i...

Bulk-type all-solid-state batteries (SSBs) are receiving much attention as next-generation energy storage technology with potentially improved safety and higher power and energy densities (over a w...

Nickel-rich NCMs [Li1+x(Ni1–y–zCoyMnz)1–xO2] are among the most promising cathode materials for use in high-energy lithium-ion batteries. While the cathode composition can vary depending on the app...

Ni-rich layered LiNi1-x-yCoxMnyO2 (NCM, x + y ≤ 0.2) is an intensively studied class of cathode active materials for lithium-ion batteries, offering the advantage of high specific capacities. However, their reactivity is also one of the major issues limiting the lifetime of the batteries. NCM degradation, in literature, is mostly explained both by disintegration of secondary particles (large anisotropic volume changes during lithiation/delithiation) and by formation of rock-salt like phases at the grain surfaces at high potential with related oxygen loss. Here, we report the presence of intragranular nanopores in Li1+x(Ni0.85Co0.1Mn0.05)1-xO2 (NCM851005) and track their morphological evolution from pristine to cycled material (200 and 500 cycles) using aberration-corrected scanning transmission electron microscopy (STEM), electron energy loss spectroscopy, energy dispersive X-ray spectroscopy, and time-of-flight secondary ion mass spectrometry. Pores are already found in the primary particles of pristine material. Any potential effect of TEM sample preparation on the formation of nanopores is ruled out by performing thickness series measurements on the lamellae produced by focused ion beam milling. The presence of nanopores in pristine NCM851005 is in sharp contrast to previously observed pore formation during electrochemical cycling or heating. The intragranular pores have a diameter in the range between 10 and 50 nm with a distinct morphology that changes during cycling operation. A rock-salt like region is observed at the pore boundaries even in pristine material, and these regions grow with prolonged cycling. It is suggested that the presence of nanopores strongly affects the degradation of high-Ni NCM, as the pore surfaces apparently increase (i) oxygen loss, (ii) formation of rock-salt regions, and (iii) strain-induced effects within the primary grains. High-resolution STEM demonstrates that nanopores are a source of intragranular cracking during cycling.

Li-rich disordered rock-salt oxides such as Li1.2Ni1/3Ti1/3Mo2/15O2 are receiving increasing attention as high-capacity cathodes due to their potential as high-energy materials with variable elemen...

Alumina aerogels are obtained by supercritical drying (SCD) in four solvents of different chemical natures. The phase transformations, the morphological changes, and the thermal stability during heat treatment in the range 20–1200 °C are investigated. The as-prepared samples obtained by SCD in MeOH are identified as crystalline aluminum hydroxide methoxide, and those obtained by SCD in i-PrOH consist of alumina with small size of crystallite grains. In contrast to alcohol-dried samples, the initial ether-dried aerogels are amorphous (as determined by X-ray diffraction). Calcination of the samples causes their crystallization and recrystallization. After heat treatment at 1200 °C, all samples consisted only of the α-alumina phase. TEM study demonstrated that the nature of the solvent used for SCD significantly affects the morphology of the aerogels. Low-temperature nitrogen adsorption investigation of the aerogel samples confirms the influence of the nature of supercritical fluid (SCF) on the structure of ...