Oligonucleotides are indispensable tools in diagnostics, therapeutic applications and molecular biology. The low base pairing strength of thymine with adenine complicates their use. Ethynylpyridone C-nucleosides are analogs of thymidine that pair more strongly and with improved base selectivity, and sequences containing these analogs show improved target affinity and selectivity, but their routine use is hampered by diminished yields of solid-phase syntheses with the known building blocks. A partial loss of base protecting groups during the acidic deblocking step of chain extension cycles was identified as the cause of lower yields. Here we report the synthesis of an improved phosphoramidite building block featuring a pivaloyloxymethyl (POM) base protecting group. This building block gives oligonucleotides containing the strongly pairing ethynylmethylpyridone C-nucleoside in high yield and purity via solid-phase synthesis.
With the current global projection of over 130 million electric vehicles (EVs), there soon will be a need for battery waste management. Especially for all‐solid‐state lithium‐ion batteries (lithium ASSBs), aspects of waste management and circular economy have not been addressed so far. Within such ASSBs, the use of solid‐electrolytes like garnet‐type Li6.5La3Zr1.5Ta0.5O12 (LLZTO) may shift focus on strategies to recover not only the transition metal elements but also elements like La/Zr/Ta. In this work, we present a two‐step recycling approach using citric acid as the leaching agent to separate and recover the individual components of a model cell comprising of Li4Ti5O12 (LTO) anode, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolyte and LiNi1/3Mn1/3Co1/3O2 (NMC) cathode. We observe that by adjusting the concentration of citric acid, it was possible to separate the materials from each other without strong mixing of individual phases and also to maintain their principle performance characteristics. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability of battery components in the development of lithium ASSBs.
The Cover Feature illustrates the problems arising from the finite lifetime of a battery and the challenge to reanimate it for a second life by means of a recycling process. It shows that dead solid‐state batteries could be resurrected after digging them out of their graves by subsequent recycling via a hydrometallurgical process using citric acid. More information can be found in the Research Article by A. I. Waidha et al.
All solid-state lithium-ion batteries (lithium ASSBs) are promising candidates for their use in high energy density applications like electric vehicles (EVs). With the current global projections of over 130 million EVs on road by 2030, there soon will be a need for lithium ASSBs waste management. For lithium ASSBs, various combinations of solid electrolytes and electrode materials could be imagined, e.g., with garnet electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) and the use of a solid electrolyte might shift focus on recycling strategies. Not only the transition metals of the electrode materials will then be an important target, but also the recovery of La/Zr/Ta. In this work, we present a recycling approach based on a two-step leaching process with citric acid to separate and recover the individual components of a full model cell comprising of Li4Ti5O12 (LTO) anode, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolyte and LiNi1/3Mn1/3Co1/3O2 (NMC) cathode. By treating the complex mixture of LTO/LLZTO/NMC in this process, we manage to separate the materials from each other without strong mixing of elements between the individual phases. We show that the battery components can maintain their principle performance characteristics, demonstrating that the developed process can serve as a basis to recover functional battery materials. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability for battery components in the development of lithium ASSBs.
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