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1. Secondary Ion Mass Spectrometry Reference Materials for Lithium in Carbonaceous Matrices

   https://doi.org/10.1111/ggr.12415  

   Teichert, Zebadiah; Bose, Maitrayee; Williams, Peter; Hervig, Richard L.; Williams, Lynda B. (February 2022, Geostandards and Geoanalytical Research)

   Secondary ion mass spectrometry techniques are used to study trace elements in organic samples where matrix compositions vary spatially. This study was conducted to develop calibrations for lithium content and lithium isotope measurements in kerogen. Known concentrations of Li ions (⁶Li and⁷Li) were implanted into organic polymers, with a range of H/C and O/C ratios similar to kerogen, along with glassy carbon (SPI Glas‐22) and silicate glass (NIST SRM 612). Results show that Li content calibration factors (K*) are similar for carbonaceous samples when analysed using a 5 kV secondary ion accelerating voltage. Using a 9 kV secondary ion accelerating voltage,K* factors are negatively correlated with the sample O content, changing ~ 30% between 0 and 15 oxygen atomic %. Thus, to avoid the matrix effect related to O content, using a 5 kV secondary ion accelerating voltage is best for quantification of Li contents based on⁷Li⁺/¹²C⁺ratios. Under these analytical conditions, Li ppm (atomic) = (132 (± 8) × ⁷Li⁺/¹²C⁺) × ¹²C atom fraction of the sample measured. Lithium isotope ratio measurements of SPI Glas‐22 and NIST SRM 612 are within uncertainty; however, the organic polymer samples as a group show a 10‰ higher δ⁷Li than NIST SRM 612. 

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2. Effects of contact metamorphism on the lithium content and isotopic composition of kerogen in coal

   https://doi.org/10.1016/j.chemgeo.2022.120885  

   Teichert, Z. (May 2022, Chemical geology)

   Lithium isotopes (δ7Li) in coals have been shown to increase with thermal maturity, suggesting preferential release of 6Li from kerogen to porefluids. This has important implications for paleoclimate studies based on δ7Li of buried marine carbonates, which may incorporate Li from porefluids during recrystallization. Here, the Li content and isotopic composition of macerals from two coal seams intruded by dikes, were studied as a function of temperature across a thermal gradient into the unmetamorphosed coal. Samples were collected in Colorado (USA) from a Vermejo Fm. coal seam intruded by a mafic-lamprophyre dike and compared to a Dutch Creek No.2 coal seam intruded by felsic-porphyry dike; a potential source of Li-rich fluids. The Li-content and Li-isotope compositions of coal macerals were measured in situ by Secondary Ion Mass Spectrometry (SIMS). The macerals of the Vermejo coal samples, buried to VRo 0.68% (Tmax = 104 ◦C), contained <1.5 μg/g Li with an average vitrinite δ7Li of −28.4 ± 1.6‰, while liptinite and inertinite were heavier, averaging −15.4 ± 3.6‰ and − 10.5 ± 3.7‰, respectively. The contact metamorphosed vitrinite/coke showed the greatest change with temperature with δ7Li 18 to 37‰ heavier than the unmetamorphosed vitrinite. The Dutch Creek coal, buried to VRo 1.15% (Tmax = 147 ◦C), prior to dike emplacement, may have released Li during burial, as less isotopic change was observed between contact metamorphosed and unmetamorphosed macerals. Overall, Li contents were < 1 μg/g, and the vitrinite in metamorphosed coal had δ7Li values 8 to 21‰ heavier than the unmetamorphosed coal. SIMS measurements on macerals near the dike did not show an increase in Li-content indicative of Li derived from dike fluids, however previous bulk measurements that included silicates showed slightly higher (2-3 μg/g) Li-contents near the dike, suggesting possible Li incorporation from dike fluid into metamorphic silicates. A negative correlation was observed between Li-content and 12C+/30Si+ count ratios, indicating that at metamorphic temperatures Li becomes concentrated in silicates. 

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3. Optimization of lithium isotope analysis in geological materials by quadrupole ICP-MS

   https://doi.org/10.1039/C9JA00175A  

   Liu, Xiao-Ming; Li, Wenshuai (July 2019, Journal of Analytical Atomic Spectrometry)

   This study develops and optimizes a new protocol to measure lithium isotope ratios using a single collector quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) operated under hot plasma (1550 W) conditions with a sample–standard bracketing method. Our Q-ICP-MS method reduces sample consumption to 2.5 ng of Li and achieves a high long-term precision of 1.1‰ (2SD). This Q-ICP-MS method exhibits high matrix tolerance (Na/Li < 100), suitable for ng-sized and high-matrix geological samples. We also developed a dual-column system for Li separation, with large loading capacity (29.6 meq), complete recovery (∼100%) and satisfactory purification (Na/Li m m −1 < 1), as well as a fixed elution range for Li fractions (28–60 mL). This new chromatography method has been applied to chemically diverse materials, producing consistent results. In addition, we report the Li isotope compositions of 13 geostandards, and our measurements agree well with reported data within analytical uncertainties. This study documents that Li element concentration and Li isotope composition can be routinely measured using a single collector ICP-MS, which is convenient and commercially affordable for future Li isotope research across the fields of Earth and Environmental Sciences. 

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4. MOF-Enabled Ion-Regulating Gel Electrolyte for Long-Cycling Lithium Metal Batteries Under High Voltage

   https://doi.org/10.1002/smll.202106225  

   Fu, Xuewei; Hurlock, J. Matthew; Ding, Chenfeng; Li, Xiaoyu; Zhang, Qiang; Zhong, Wei-Hong (December 2021, Small)

   High-voltage lithium metal batteries (LMBs) are a promising high-energy density energy storage system. However, their practical implementations are impeded by short lifespan due to uncontrolled lithium dendrite growth, narrow electrochemical stability window, and safety concerns of liquid electrolytes. Here, a porous composite aerogel is reported as the gel electrolyte (GE) matrix, made of metal–organic framework (MOF)@bacterial cellulose (BC), to enable long-life LMBs under high voltage. The effectiveness of suppressing dendrite growth is achieved by regulating ion deposition and facilitating ion conduction. Specifically, two hierarchical mesoporous Zr-based MOFs with different organic linkers, that is, UiO-66 and NH2-UiO-66, are embedded into BC aerogel skeletons. The results indicate that NH2-UiO-66 with anionphilic linkers is more effective in increasing the Li+ transference number; the intermolecular interactions between BC and NH2-UiO-66 markedly increase the electrochemical stability. The resulting GE shows high ionic conductivity (≈1 mS cm−1), high Li+ transference number (0.82), wide electrochemical stability window (4.9 V), and excellent thermal stability. Incorporating this GE in a symmetrical Li cell successfully prolongs the cycle life to 1200 h. Paired with the Ni-rich LiNiCoAlO2 (Ni: Co: Al = 8.15:1.5:0.35, NCA) cathode, the NH2-UiO-66@BC GE significantly improves the capacity, rate performance, and cycle stability, manifesting its feasibility to operate under high voltage. 

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5. High-performance all-solid-state batteries enabled by salt bonding to perovskite in poly(ethylene oxide)

   https://doi.org/10.1073/pnas.1907507116  

   Xu, Henghui; Chien, Po-Hsiu; Shi, Jianjian; Li, Yutao; Wu, Nan; Liu, Yuanyue; Hu, Yan-Yan; Goodenough, John B. (September 2019, Proceedings of the National Academy of Sciences)

   Flexible and low-cost poly(ethylene oxide) (PEO)-based electrolytes are promising for all-solid-state Li-metal batteries because of their compatibility with a metallic lithium anode. However, the low room-temperature Li-ion conductivity of PEO solid electrolytes and severe lithium-dendrite growth limit their application in high-energy Li-metal batteries. Here we prepared a PEO/perovskite Li 3/8 Sr 7/16 Ta 3/4 Zr 1/4 O 3 composite electrolyte with a Li-ion conductivity of 5.4 × 10 −5 and 3.5 × 10 −4 S cm −1 at 25 and 45 °C, respectively; the strong interaction between the F − of TFSI − (bis-trifluoromethanesulfonimide) and the surface Ta 5+ of the perovskite improves the Li-ion transport at the PEO/perovskite interface. A symmetric Li/composite electrolyte/Li cell shows an excellent cyclability at a high current density up to 0.6 mA cm −2 . A solid electrolyte interphase layer formed in situ between the metallic lithium anode and the composite electrolyte suppresses lithium-dendrite formation and growth. All-solid-state Li|LiFePO 4 and high-voltage Li|LiNi 0.8 Mn 0.1 Co 0.1 O 2 batteries with the composite electrolyte have an impressive performance with high Coulombic efficiencies, small overpotentials, and good cycling stability. 

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