An efficient method for the preparation of silyl esters of diphosphoric, phosphoric, and phosphorous acid

Unanticipated Mechanism of the Trimethylsilyl Motif in Electrolyte Additives on Nickel-Rich Cathodes in Lithium-Ion Batteries

The introduction of a trimethylsilyl (TMS) motif in electrolyte additives for lithium-ion batteries is regarded as an effectual approach to remove corrosive hydrofluoric acid (HF) that structurally and compositionally damages the electrode-electrolyte interface and gives rise to transition metal dissolution from the cathode. Herein, we present that electrolyte additives with TMS moieties lead to continued capacity loss of polycrystalline (PC)-LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathodes coupled with graphite anodes compared to additives without TMS as the cycle progresses. Through a comparative study using electrolyte additives with and without TMS moieties, it is revealed that the TMS group is prone to react with residual lithium compounds, in particular, lithium hydroxide (LiOH) on the PC-NCM811 cathode, and the resulting TMS-OH triggers the decomposition of PF₅ created by the autocatalytic decomposition of LiPF₆ that generates reactive species, namely, HF and POF₃. This work aims to offer a way to build favorable interface structures for Ni-rich cathodes covered with residual lithium compounds through a study to figure out the roles of TMS moieties of electrolyte additives.

Five- and six-fold coordinated silicon in silicodiphosphonates: short range order investigation by solid-state NMR spectroscopy

Silicodiphosphonates synthesized by two different pathways show interesting chemical shifts of five- and sixfold coordinated silicon.

Synthesis and Characterization of Silylated Phosphonium [P(OSiMe3)4]+ and Phosphate [O2P(OSiMe3)2]- Salts

Starting from an optimized synthesis of silylated phosphoric acid, OP(OSiMe₃)₃, a borate salt bearing the [P(OSiMe₃)₄]⁺ cation was generated in the reaction of OP(OSiMe₃)₃ with [Me₃Si-H-SiMe₃][B(C₆F₅)₄], isolated, and fully characterized. Analogously to the protonated species, phosphoric acid (H₃PO₄) reaction of OP(OSiMe₃)₃ with a base led to the formation of the unknown [O₂P(OSiMe₃)₂]^- anion, which could be crystallized as potassium salt and structurally characterized, too. Both [P(OSiMe₃)₄]⁺ and [O₂P(OSiMe₃)₂]^- can be regarded as the formal autoprotolysis products of OP(OSiMe₃)₃.

Lifetime limit of tris(trimethylsilyl) phosphite as electrolyte additive for high voltage lithium ion batteries

In this work, a failure mechanism of tris(trimethylsilyl)phosphite (TMSPi), as a popular additive in a LiPF₆ containing electrolyte for lithium ion batteries, is proposed and elucidated for the first time.

Arabidopsis thaliana isoprenyl diphosphate synthases produce the C25 intermediate geranylfarnesyl diphosphate

Isoprenyl diphosphate synthases (IDSs) catalyze some of the most basic steps in terpene biosynthesis by producing the prenyl diphosphate precursors of each of the various terpenoid classes. Most plants investigated have distinct enzymes that produce the short-chain all-trans (E) prenyl diphosphates geranyl diphosphate (GDP, C10 ), farnesyl diphosphate (FDP, C15 ) or geranylgeranyl diphosphate (GGDP, C20 ). In the genome of Arabidopsis thaliana, 15 trans-product-forming IDSs are present. Ten of these have recently been shown to produce GGDP by genetic complementation of a carotenoid pathway engineered into Escherichia coli. When verifying the product pattern of IDSs producing GGDP by a new LC-MS/MS procedure, we found that five of these IDSs produce geranylfarnesyl diphosphate (GFDP, C25 ) instead of GGDP as their major product in enzyme assays performed in vitro. Over-expression of one of the GFDP synthases in A. thaliana confirmed the production of GFDP in vivo. Enzyme assays with A. thaliana protein extracts from roots but not other organs showed formation of GFDP. Furthermore, GFDP itself was detected in root extracts. Subcellular localization studies in leaves indicated that four of the GFDP synthases were targeted to the plastoglobules of the chloroplast and one was targeted to the mitochondria. Sequence comparison and mutational studies showed that the size of the R group of the 5th amino acid residue N-terminal to the first aspartate-rich motif is responsible for C25 versus C20 product formation, with smaller R groups (Ala and Ser) resulting in GGDP (C20 ) as a product and a larger R group (Met) resulting in GFDP (C25 ).