Four non-toxic, highly active and robust complexes have been used in the ring opening polymerisation of non-purifed lactide to substitute Sn(Oct)2.

Garnet-based all-solid-state batteries (ASBs) with high energy density require composite cathodes with high areal loading and high-capacity cathode active materials. While all ceramic cathodes can typically be manufactured via cosintering, the elevated temperatures necessary for this process pose challenges with respect to material compatibility. High-capacity cathode active materials like Ni-rich LiNi x Co y Mn1–x–y O2 (NCM) show insufficient material compatibility toward the solid electrolyte Li6.45Al0.05La3Zr1.6Ta0.4O12 (LLZO:Ta) during cosintering, leading to the formation of highly resistive interphases. We investigated this secondary phase formation both experimentally and via density functional theory calculation to get a mechanistic understanding of the cosintering behavior of LLZO:Ta with NCM111 and Ni-rich NCM811. Furthermore, we employed B doping of both NCM materials in order to assess its impact on the cation interchange and subsequent secondary phase formation. While secondary phases were formed for all four NCM materials, their onset temperature, nature, and amount strongly depend on the NCM composition and doping. Surprisingly, Ni-rich NCM811 turned out to be the most promising cathode active material for the combination with garnet-type LLZO:Ta. As proof of concept, fully inorganic, ceramic all-solid-state lithium batteries featuring only a Li-metal anode, an LLZO:Ta separator, and a composite cathode, consisting of LLZO:Ta, Li3BO3, and NCM811, were prepared by conventional sintering. The purely inorganic full cells delivered a high specific areal discharge capacity of 0.7 mA h cm–2 in the initial cycle.

Doping of Ni-rich cathode active materials with boron is a promising way to improve their cycling stability and mitigate their degradation, but it is still not understood how this effect is achieved and where the boron is located. To receive deeper insights into the impact of doping on atomic and microscale properties, B-doped Li[Ni 0. 8 Co 0.1 Mn 0 .1 ]O 2 (NCM811) cathode materials were synthesized by a hydroxide coprecipitation as a model compound to verify the presence and location of boron in B-doped, Ni-rich NCM, as well as its impact on the microstructure and electrochemical properties, by a combined experimental and theoretical approach. Besides X-ray diffraction and Rietveld refinement, DFT calculation was used to find the preferred site of boron absorption and its effect on the NCM lattice parameters. It is found that boron shows a trigonal planar and tetrahedral coordination to oxygen in the Ni layers, leading to a slight increase in lattice parameter c through an electrostatic interaction with Li ions. Therefore, B-doping of NCM811 affects the crystal structure and cation disorder and leads to a change in primary particle size and shape. To experimentally prove that the observations are caused by boron incorporated into the NCM lattice, we detected, quantified, and localized boron in 2 mol % Bdoped NCM811 by ion beam analysis and TOF-SIMS. It was possible to quantify boron by NRA with a depth resolution of 2 μm. We found a boron enrichment on the agglomerate surface but also, more importantly, a significant high and constant boron concentration in the interior of the primary particles near the surface, which experimentally verifies that boron is incorporated into the NCM811 lattice.