Li Source Research Articles

Evolution of lithium in the disc of the Galaxy and the role of novae

Lithium plays a crucial role in probing stellar physics, stellar and primordial nucleosynthesis, and the chemical evolution of the Galaxy. Stars are considered to be the main source of Li, yet the identity of its primary stellar producer has long been a matter of debate. In light of recent theoretical and observational results, we investigate in this study the role of two candidate sources of Li enrichment in the Milky Way, namely asymptotic giant branch (AGB) stars and, in particular, novae. We utilised a one-zone Galactic chemical evolution (GCE) model to assess the viability of AGB stars and novae as stellar sources of Li. We used recent theoretical Li yields for AGB stars, while for novae we adopted observationally inferred Li yields and recently derived delay time distributions (DTDs). Subsequently, we extended our analysis by using a multi-zone model with radial migration to investigate spatial variations in the evolution of Li across the Milky Way disc and compared the results with observational data for field stars and open clusters. Our analysis shows that AGB stars clearly fail to reproduce the meteoritic Li abundance. In contrast, novae appear as promising candidates within the adopted framework, allowing us to quantify the contribution of each Li source at the Sun's formation and today. Our multi-zone model reveals the role of the differences in the DTDs of Type Ia supernovae and novae in shaping the evolution of Li in the various galactic zones. Its results are in fair agreement with the observational data for most open clusters, but small discrepancies appear in the outer disc.

Artificial Electron Channels Enable Contact Prelithiation of Li-Ion Battery Anodes with Ultrahigh Li-Source Utilization.

Contact prelithiation is widely used for compensating the initial capacity loss of lithium-ion batteries (LIBs). However, the low Li-source utilization suffering from the deteriorated contact interfaces results in cycling degeneration. Herein, Li-Ag alloy-based artificial electron channels (AECs) are established in Li source/graphite anode contact interfaces to promote Li-source conversion. Due to the shielding effect of the Li-Ag alloy (50 at. % Li) on Li-ion diffusion, the dry-state corrosion of contact interfaces is restricted. The unblocked electronic conduction across the AEC-involved interface not only facilitates the Li source conversion but also accelerates the prelithiation kinetics during the wet-state process, resulting in an ultrahigh Li-source utilization (90.7%). Thereby, implementing AEC-assisted prelithiation in a LiNi0.5Co0.2Mn0.3O2 pouch cell yields a 35.8% increase in energy density and stable cycling over 600 cycles. This finding affords significant insights into the construction of an efficient prelithiation technology toward the development of high-energy LIBs.

Artificial Electron Channels Enable Contact Prelithiation of Li‐Ion Battery Anodes with Ultrahigh Li‐Source Utilization

Contact prelithiation is widely used for compensating the initial capacity loss of lithium‐ion batteries (LIBs). However, the low Li‐source utilization suffering from the deteriorated contact interfaces results in cycling degeneration. Herein, Li−Ag alloy‐based artificial electron channels (AECs) are established in Li source/graphite anode contact interfaces to promote Li‐source conversion. Due to the shielding effect of the Li−Ag alloy (50 at. % Li) on Li‐ion diffusion, the dry‐state corrosion of contact interfaces is restricted. The unblocked electronic conduction across the AEC‐involved interface not only facilitates the Li source conversion but also accelerates the prelithiation kinetics during the wet‐state process, resulting in an ultrahigh Li‐source utilization (90.7%). Thereby, implementing AEC‐assisted prelithiation in a LiNi0.5Co0.2Mn0.3O2 pouch cell yields a 35.8% increase in energy density and stable cycling over 600 cycles. This finding affords significant insights into the construction of an efficient prelithiation technology toward the development of high‐energy LIBs.

Reveal the capacity loss of lithium metal batteries through analytical techniques

AbstractHigh energy density and stable long cycle are the basic requirements for an ideal battery. At present, lithium (Li) metal anode is regarded as one of the most promising anode materials, but it still faces major problems in terms of capacity fading and safe and stable long‐term cycle. The reason for the continuous fading of Li anode capacity is mainly due to the loss of active Li source, and the loss of Li source is mainly due to the continuous generation of dead Li. At the same time, the unstable interface and dendrite growth of Li anodes during the Li plating/delithiation process eventually lead to battery safety issues. In fact, recent studies have shown that the disordered expansion of dendrites is the main reason for the infinite generation of dead Li. Therefore, here we take different detection techniques as clues, review the exploration process of qualitative and quantitative research on the source and mechanism of Li capacity loss, and summarize the strategies to reduce dead Li generation and capacity fading by inhibiting dendrite formation. In particular, we give suggestions on the development of advanced testing methods on how to further study the problem of dead Li, and also give relevant strategy suggestions on how to completely solve the problem of capacity loss in the future, with the main goal of suppressing dendrites.

Retrieving lost Li in LIBs for co-regeneration of spent anode and cathode materials

Direct regeneration of spent Li-ion battery electrode materials has garnered considerable attention due to its streamlined procedure, low energy consumption, and high economic viability. Typically, an Li source is required to address the vacant Li defects in spent cathodes for regeneration, while the removal of residual Li is crucial for regenerating spent anodes. Here, given our discovery that approximately 65 % of the residual Li in spent graphite demonstrates reactivity with water, we propose a straightforward water extraction method for purifying and regenerating spent graphite anode. By carefully controlling the concentrations of OH- and Li+ ions in the obtained Li-rich solution, it can be directly used to relithiate spent NCM cathodes. In this method, Li+ ions lost from the cathode during electrochemical cycling were reintroduced back into the cathode via aqueous relithiation, eliminating the need for additional Li sources to repair the Li deficiencies in spent cathode, effectively reducing recycling costs and minimizing the environmental impact associated with raw materials. The regenerated NCM cathode and graphite anode demonstrated specific capacities of 163 mAh/g and 386 mAh/g at a rate of 0.1C, respectively, both reaching the performance levels of pristine materials. Importantly, compared to traditional direct recycling methods, the Li-retrieving regeneration method reduced greenhouse gas emissions by 16 %, energy consumption by 17 %, water consumption by 17 %, and overall recycling costs by 12 %.

Geochemical characteristics, Li source and genesis mechanism of thermal mineral water in Sichuan Basin, SW China

Thermal mineral water (temperature >25 °C) is a valuable resource, especially when it contains a certain amount of Li. In this study, an attempt was made to elucidate the factors affecting spatial distribution of lithium (Li) resources and interpret the formation mechanisms of thermal mineral waters in the Sichuan Basin. The spatial distribution, reservoir temperatures, and hydrochemical characteristics of thermal mineral waters were systematically analyzed in the Sichuan Basin, preliminarily revealing Li sources through hydrochemical methods. Results are showed as follows: (1) The Li-bearing (Li ≥ 1 mg/L) thermal mineral waters are mainly distributed in the southwestern part of the Sichuan Basin. There are three sites of thermal mineral waters with Li content greater than 25 mg/L with the hydrochemical type of Cl–Na type: Pengji Well (37.7 mg/L), Foguanghu Well (99.5 mg/L) and Zhougongshan New Well (118.0 mg/L). Among them, the Foguanghu Geothermal Well and the Zhougongshan New Well have high Li content and low Mg/Li (10.7 and 2.5), indicating great potential for utilization. (2) The Li-bearing thermal mineral waters are mainly formed in the fissure and pore reservoirs of the Middle–Lower Triassic. They are mainly affected by the dissolution of halite minerals and the deeply buried ancient seawater of the Triassic. The Li-bearing thermal mineral waters possess high contents of total dissolve solids (TDS) (4.3–230.0 g/L), Cl (0.7–142.9 g/L), Na (0.5–76.7 g/L), K (0.1–52.0 g/L), B (4.1–739.6 mg/L), and Li (1.5–118.0 mg/L). Moreover, the temperature of the geothermal reservoir ranges from 40 to 150 °C. The geothermal reservoir temperatures calculated by K–Mg and Mg–Li geothermometers are positively correlated with the Li content. (3) The Li source of the thermal mineral waters of the Sichuan Basin are dominated by multiple factors: first, Li concentration by evaporation, concentration and deep-seated metamorphism of ancient Triassic seawater; second, water–rock interaction between deep thermal mineral waters and mung bean rock or Emeishan basalt; and third, active tectonic activity and deep faulting induced upward flow of Li in deep fluids. This research enhances understanding of the formation of thermal mineral waters in the Sichuan Basin, offering scientific basis for the exploitation of Li resource.

Identifying critical features of iron phosphate particle for lithium preference

One-dimensional (1D) olivine iron phosphate (FePO4) is widely proposed for electrochemical lithium (Li) extraction from dilute water sources, however, significant variations in Li selectivity were observed for particles with different physical attributes. Understanding how particle features influence Li and sodium (Na) co-intercalation is crucial for system design and enhancing Li selectivity. Here, we investigate a series of FePO4 particles with various features and revealed the importance of harnessing kinetic and chemo-mechanical barrier difference between lithiation and sodiation to promote selectivity. The thermodynamic preference of FePO4 provides baseline of selectivity while the particle features are critical to induce different kinetic pathways and barriers, resulting in different Li to Na selectivity from 6.2 × 102 to 2.3 × 104. Importantly, we categorize the FePO4 particles into two groups based on their distinctly paired phase evolutions upon lithiation and sodiation, and generate quantitative correlation maps among Li preference, morphological features, and electrochemical properties. By selecting FePO4 particles with specific features, we demonstrate fast (636 mA/g) Li extraction from a high Li source (1: 100 Li to Na) with (96.6 ± 0.2)% purity, and high selectivity (2.3 × 104) from a low Li source (1: 1000 Li to Na) with (95.8 ± 0.3)% purity in a single step.

Charge Carrier Dynamics of the Mixed Conducting Interphase in All‐Solid‐State Batteries: Lithiated Li1.3Al0.3Ti1.7(PO4)3 as a Case Study

AbstractAll‐solid‐state batteries relying on Li metal as negative electrode material and a ceramic electrolyte may severely suffer from unwanted interfacial processes. Here, Li1.3Al0.3Ti1.7(PO4)3 (LATP) serve as a model electrolyte which is known to form an ionic‐electronic, that is, mixed conducting interphase (MCI) when in contact with metallic Li or any other Li source. Li1.3+xAl0.3Ti1.7(PO4)3 with x = 0.2, 0.6 and 1.3 is prepared via ex situ chemical lithiation to mimic the formation of MCIs taking place otherwise operando. The preparation of large amounts of lithiated LATP with controlled Li contents allowed us to use nuclear and electric techniques to study local structures and ionic/electronic dynamics in detail. The results point to the formation of a core‐shell two‐phase morphology with the Li‐rich Li3Al0.3Ti1.7(PO4)3 phase covering the nonlithiated Li‐poor regions. The originally poor electronic conductivity σeon of 6.5 × 10−12 S cm−1 (293 K) increases by ≈3 orders of magnitude, hence reaching the order of 6.6 × 10−9 S cm−1 for x = 0.6. At even higher loadings (x = 1.3), a decrease in conductivity is seen, i.e., not exceeding alarming values for σeon. Quantifying electronic and ionic transport processes will help assessing the extent of damage through MCI formation and discussing whether any strategies to mitigate such formation is necessary at all.

Brine-granite interaction and lithium leaching in a continental rift (Soultz-sous-Forêts, Rhine Graben, France)

At Soultz-sous-Forêts, the geothermal reservoir was identified around thirty years ago by drilling down to depths of 5000 m. It comprises the base of the Mesozoic series and the underlying fractured granitic basement. Fluid inclusion data have shown near-continuous mixing trends between two main fluid end-members: i) brines interpreted as of primary evaporitic origin with low Cl/ Br ratio (100−200), which evolved then by fluid-rock interaction in the granite, and ii) dilute recharge fluids originating from high points. These mixing terms cover much wider ranges than the pumped geothermal fluid. The brines identified at depth of up to 5000 m indicate very significant penetration from the sedimentary series, and the extent of fluid mixing is most likely favoured by the dynamics of extension and convection developed by the heat flow associated with the continental rift. LA-ICP-MS and crush-leach analyses of the fluid inclusions show that lithium concentrations are high (up to 1000 ppm), up to three orders of magnitude higher than seawater. Therefore, the enrichment of the reservoir in lithium and other metals cannot be explained by the pre-concentration of primary brines by evaporation alone. Enrichment occurs in damage envelopes along fault zones through fluid-rock interactions and illite (+ quartz) development at the expense of ferromagnesian phyllosilicates, constituting the primary Li source with a content of 300 to 700 ppm Li. Using a simplified assessment of the ratio between the lithium available in the rock around 30–50 ppm, and the lithium in solution (200 ppm) in current fluids, an extraction of 2.5% to 10% of the Li contained in the granite can contribute to the mass of Li available in the reservoir. This average estimate is compatible with the much greater losses identified in damage areas where Li concentrations in weathered granite fall to values of 10 to 16 ppm.

Effects of the Hydroxy-Regulated Li-Montmorillonite Atomic Interface Arrangement on Li Cycle of Marine Sedimentation and pH.

The reaction of ubiquitous clay is related to the global cycle of the key metals, but the relationship between the Li occurrence interface and the sedimentation in the Li cycle remains unclear. We investigated the atomic interface arrangement of Li-montmorillonite (Li-Mt) during low-temperature water-rock reactions and Li migration. The results show that, in Cl-rich systems, deprotonation and exposure of Na adsorption sites cause Li enrichment and O pairing, which lead to the weakening of the shielding effect of Mt on anions and the formation of a Mt-Li-Cl atomically interfacial arrangement. Only up to 20.3% of the Li is contained in the atomic interface of Li-Mt. In F-rich system, the dehydroxylation of F paired with Al in octahedral sites causes Li accumulation via local crystallization of LiF, and co-complexation of F and Li forms a Mt(Al)-F-Li atomic interface, in which up to 46.8% of the Li is enriched by the Mt. The participation of F and Cl in the complexation intensifies lattice collapse of the Li-Mt edge. The sedimentation velocity decreases with the smaller particle size affected by the Li loading. Lithium leached from igneous rocks serves as the marine Li source, which contributes up to 99.8% and 99.5% of the Li in Cl- and F-rich systems, respectively. The response of Mt(OH) to Li migration with a time accumulating effect may make an important regulatory of oceanic pH by either acidification or alkalization.

Improving electrochemical performance of Ni-rich layered cathode material with combining Co-enriched compositional gradient and radial microstructure

Ni-rich complex layered oxides LiNixMnyCozO2 (x > 0.85) with a combined Ni/Co concentration gradient and radially oriented elongated plate-like primary particles were synthesized with hydrothermal microwave-assisted treatment of an as-prepared mixed hydroxide precursor with aqueous solution of Co source and urea followed by a high temperature annealing with a Li source. The radial distribution of plate-like primary crystallites in microwave-treated materials was achieved through Co-enrichment at the surface, which likely triggered the surface-to-bulk growth of plate-like particles rather than isotropic octahedral crystallites. The Co-modified cathode materials demonstrate greatly improved cycling stability (capacity fade per cycle of 0.04 ± 0.01%) compared to unmodified Ni-rich NMCs (capacity fade per cycle of 0.13 ± 0.02%) with similar Ni concentration, as well as good rate capability (215, 210, 199, 189, 178 and 160 mAh/g at C/10, C/5, C/2, 1C, 2C, and 5C rates at 2.7–4.3V vs Li/Li+). Enhanced electrochemical performance is linked to the improved mechanical integrity, which was achieved through radial microstructure organization of the agglomerates triggered by Co concentration gradient, suppressing the intragranular crack formation.

Hierarchical Li electrochemistry using alloy-type anode for high-energy-density Li metal batteries

Exploiting thin Li metal anode is essential for high-energy-density battery, but is severely plagued by the poor processability of Li, as well as the uncontrollable Li plating/stripping behaviors and Li/electrolyte interface. Herein, a thickness/capacity-adjustable thin alloy-type Li/LiZn@Cu anode is fabricated for high-energy-density Li metal batteries. The as-formed lithophilic LiZn alloy in Li/LiZn@Cu anode can effectively regulate Li plating/stripping and stabilize the Li/electrolyte interface to deliver the hierarchical Li electrochemistry. Upon charging, the Li/LiZn@Cu anode firstly acts as Li source for homogeneous Li extraction. At the end of charging, the de-alloy of LiZn nanostructures further supplements the Li extraction, actually playing the Li compensation role in battery cycling. While upon discharging, the LiZn alloy forms just at the beginning, thereby regulating the following Li homogeneous deposition. The reversibility of such an interesting process is undoubtedly verified from the electrochemistry and in-situ XRD characterization. This work sheds light on the facile fabrication of practical Li metal anodes and useful Li compensation materials for high-energy-density Li metal batteries.

One-step regeneration and upgrading of spent LiFePO4 cathodes with phytic acid.

The regeneration and upgrading of spent LiFePO4 cathodes (S-LFP) were achieved via a one-step hydrothermal treatment. The reducing effect of phytic acid could restore the degraded structure associated with an aqueous Li source. Meanwhile, Li ions are easily chelated by phytic acid groups, and a Li3PO4 coating layer could be formed to reconstruct the surface of the LFP. The regenerated LFP exhibits faster reaction kinetics, larger high-rate charge/discharge capacity, and better cycling performance than commercial LFPs, suggesting that our proposed strategy is a promising technology for the recovery of spent cathode materials.

Characterisation of Molten Lithium Carbonate Corrosion on SiC Heating Elements Using Raman Spectroscopy

The synthesis of lithium battery materials involves the use of muffle furnaces operating with SiC type heating elements. Usually, the industrial SiC heating element is protected by passive oxidation forming a protective silica film on the surface of the element. However, this strategy is not suitable for heating elements that operate in a Li-rich environment. A preliminary study has recently been completed to develop an understanding on the degradation of silicon carbide heating elements under the exposure to lithia. After basic characterisation of the SiC rod and its oxidation in air, its reaction products in the presence of Li was studied. The SiC rod was reacted with a likely Li source, Li2CO3, in three different % Li concentration environments through vapour-phase, wetting and full-immersion studies, particularly at the temperature just above the Li2CO3 melting point in delivering accelerated ageing. The characterisation was achieved via an integrative data analysis through the coordination of Raman, XRD, and Energy dispersive X-ray analysis (EDX) techniques. We found that molten Li2CO3 reacts with the silica surface layer of the element forming three main lithium silicates (LixSiyOx/2+2y). The degradation of surface silica into non-adherent lithium silicate leads to a speeding-up of the SiC oxidation process. Both processes eventually lead to a complete structural failure of the SiC rod. We performed a long-term vapour phase lithium attack experiment characterising the SiC after regular time intervals solely by Raman spectroscopy. Initially, a library of Raman spectra for the commonly encountered compounds in the Si-Li-O system was obtained from specifically synthesised stoichiometric compounds. In doing so, the reaction products at different reaction time intervals can be clearly identified, demonstrating the utility of Raman characterisation in corrosion studies.

Implanting Transition Metal into Li2O‐Based Cathode Prelithiation Agent for High‐Energy‐Density and Long‐Life Li‐Ion Batteries

AbstractCompensating the irreversible loss of limited active lithium (Li) is essentially important for improving the energy‐density and cycle‐life of practical Li‐ion battery full‐cell, especially after employing high‐capacity but low initial coulombic efficiency anode candidates. Introducing prelithiation agent can provide additional Li source for such compensation. Herein, we precisely implant trace Co (extracted from transition metal oxide) into the Li site of Li2O, obtaining (Li0.66Co0.11□0.23)2O (CLO) cathode prelithiation agent. The synergistic formation of Li vacancies and Co‐derived catalysis efficiently enhance the inherent conductivity and weaken the Li−O interaction of Li2O, which facilitates its anionic oxidation to peroxo/superoxo species and gaseous O2, achieving 1642.7 mAh/g~Li2O prelithiation capacity (≈980 mAh/g for prelithiation agent). Coupled 6.5 wt % CLO‐based prelithiation agent with LiCoO2 cathode, substantial additional Li source stored within CLO is efficiently released to compensate the Li consumption on the SiO/C anode, achieving 270 Wh/kg pouch‐type full‐cell with 92 % capacity retention after 1000 cycles.

Implanting Transition Metal into Li2 O-Based Cathode Prelithiation Agent for High-Energy-Density and Long-Life Li-Ion Batteries.

Compensating the irreversible loss of limited active lithium (Li) is essentially important for improving the energy-density and cycle-life of practical Li-ion battery full-cell, especially after employing high-capacity but low initial coulombic efficiency anode candidates. Introducing prelithiation agent can provide additional Li source for such compensation. Herein, we precisely implant trace Co (extracted from transition metal oxide) into the Li site of Li2 O, obtaining (Li0.66 Co0.11 □0.23 )2 O (CLO) cathode prelithiation agent. The synergistic formation of Li vacancies and Co-derived catalysis efficiently enhance the inherent conductivity and weaken the Li-O interaction of Li2 O, which facilitates its anionic oxidation to peroxo/superoxo species and gaseous O2 , achieving 1642.7 mAh/g~Li2O prelithiation capacity (≈980 mAh/g for prelithiation agent). Coupled 6.5 wt % CLO-based prelithiation agent with LiCoO2 cathode, substantial additional Li source stored within CLO is efficiently released to compensate the Li consumption on the SiO/C anode, achieving 270 Wh/kg pouch-type full-cell with 92 % capacity retention after 1000 cycles.

Simultaneous anodic de-lithiation/cathodic lithium-embedded regeneration method for recycling of spent LiFePO4 battery

The widespread use of lithium-ion batteries for energy storage will result in millions of tons of scrapped LiFePO4 (LFP) batteries. Current recycling technologies for LFP cathode materials require harsh acid treatments and are expensive. Hence, in this work, an ingenious electrochemical method is developed to recycle scrapped LFP. Specifically, through the charging/discharging process of an electrolytic system in which both the cathode and anode are scrapped LFP, the anode is de-lithiated to obtain FePO4 (FP), meanwhile, the Li+ from the anode is embedded into the cathode scrapped LFP to achieve regeneration. The experimental results show that the anode de-lithiation rate is 92 % and the cathode regeneration performance is closely related to the driving voltage. A voltage of 1 V converts the FP phase to LFP and effectively eliminates the LFP defect lattice. However, an excessive voltage (1.2 V) leads to an extremely fragile LFP crystal structure, resulting in the ineffective embedment of Li+ into the defective lattice and ineffective capacity restoration. The regenerated LFP exhibits a high restored capacity (136.5 mAh g−1 at 1 C) and excellent stability (95.32 % capacity retention after 300 cycles at 5 C). This novel method does not require an additional Li source, consumes low electrical energy (31.9 kWh t−1) and has a high current efficiency (>98 %), and it yields economic and environmental benefits that will contribute to the sustainable development of the LFP industry.

Origins and evolution of two types of Late Triassic granitic magmas in the Caolong-Xiangkariwa area of central-eastern Songpan-Ganze terrane, northern Tibet: Implications for pegmatite lithium mineralization

Pegmatite-type lithium (Li) deposits are an important source of the low-carbon energy metal, which is generally considered to be formed by the high degrees of differentiation of strongly peraluminous granitic magma. However, the question of whether the parental rocks of these peraluminous magmas are igneous or sedimentary has been widely debated. Recent studies have identified a world-class pegmatite-type Li deposit belt (up to 2800 km long) closely associated with the Late Triassic granitoids and (meta)sedimentary rocks along the West Kunlun and Hoh Xil-Songpan-Ganze terranes in northern Tibet. This study presents a comprehensive petrological, geochronological, and geochemical study on the two types of Late Triassic granitoids in the Caolong-Xiangkariwa area of the Yushu region of central-eastern Hoh Xil-Songpan-Ganze terrane in northern Tibet: type A includes the Tongtianhe-Zhenqin-Zhaduo-Zhaya-Xiangkariwa (TZX) diorites and granodiorites (218−212 Ma), and type B includes the Caolong two-mica and muscovite granites (213−205 Ma), as well as ore-barren, beryl-bearing, and spodumene-bearing pegmatite dikes (209−196 Ma). The TZX diorites and granodiorites contain variable amounts of amphibolite and biotite. They are metaluminous to slightly peraluminous with variable SiO2 (54.4−71.3 wt%), MgO (0.72−7.26 wt%) contents, and Mg# values (40−70). Some samples with low SiO2 (54.4−58.5 wt%) contents have geochemical features similar to high-Mg andesites: e.g., high MgO contents (5.24−7.26 wt%) and Mg# values (61−70). The TZX diorites and granodiorites exhibit less enriched (86Sr/87Sr)i (0.7080−0.7118) and εNd(t) (−4.8 to −8.0). By contrast, the Caolong two-mica and muscovite granites are characterized by the occurrence of abundant muscovite (plus tourmaline and garnet) and are strongly peraluminous. The Caolong granites and pegmatites are geochemically characterized by high SiO2 contents (68.8−79.8 wt%) and low MgO contents (0.01−0.10 wt%) and Mg# values (4−23). They have εNd(t) values (−8.8 to −11.4; granites: −8.8 to −10.8; pegmatites: −9.2 to −11.4) that are more enriched than the TZX diorites and granodiorites but similar to those of Songpan-Ganze (meta)sedimentary rocks (−7.4 to −12.9), and the Caolong two-mica granites have high zircon δ18O values (11.6−12.1). In addition, decreasing K/Rb ratios correspond to increasing Cs contents in K-feldspar and muscovite from the Caolong granites and pegmatites. Taking into account the Late Triassic granitoids and (meta)sedimentary rocks in the Hoh Xil-Songpan-Ganze terrane, we suggest that the TZX diorites and granodiorites were most probably formed by the partial melting of metasomatized lithospheric mantle that subsequently underwent extensive fractional crystallization. Conversely, the Caolong two-mica and muscovite granites were likely generated purely by the partial melting of (meta)sedimentary rocks rather than via the evolution of dioritic-granodioritic magmas. In summary, there were two kinds of granitic magmas with different sources in the Caolong-Xiangkariwa area. Finally, the Caolong pegmatites were most likely formed by the extreme differentiation of two-mica granitic magmas rather than the dioritic-granodioritic magmas. Therefore, the evolution of magmas derived from (meta)sedimentary rocks were most likely to have formed the Li-rich pegmatites. Moreover, these (meta)sedimentary rocks representing the ultimate Li source must have undergone strong chemical weathering, resulting in significant Li enrichment.

Degradation Behavior of Layered Structure Cathode in Sulfide Based All-Solid-State Batteries

With declaration of carbon zero in response to climate change, the importance is also being bandied about developing large-scale energy storage system, especially for electric vehicle (EV). Commercialized EV with a highest development lithium-ion batteries (LIB) could operate over 300 miles per single charging, but liquid electrolyte-based LIB gives rise to a huge risk concerning about ignition and explosion. All-solid-state batteries (ASSBs) is considered to alternative next-generation battery that have high safety advantageous with removal the risk of ignition by applying non-combustible inorganic solid-electrolytes (SEs). In case of sulfide-based ASSBs, there were progressed in performance itself at cell capacity increase and cycling characteristic due to advance in cell configuration, composite cathode, and cell fabrication technique compared to early works. Nevertheless, it is still demanded improvement related to the cathode-electrolyte interface stability, and its dominant causes are electrochemical- and chemo-mechanical problems. Therefore, most of researchers have tried to figure out the behavior of all-solid-state batteries by providing external pressure, and then resolve degradation issues including contact loss and resistive layer formation. However, in practical and commercialization aspects, the external pressured cell can be a stumbling block to scale-up from lab to large-scale ASSBs stage.In this study, we evaluated electrochemical performance using by general coin cell to investigate behavior of ASSBs, which is consisted with LiNi0.5Co0.2Mn0.3O2/Li6PS5Cl/VGCF|Li6PS5Cl|In-Li. The ASSB coin cell showed a significant capacity degradation having 59 % of capacity retention in 50th cycles, as expected. Herein, the main cause of the rapid capacity decrease is likely to be due to the accelerated physical contact loss. In addition to this, we have expanded the scope of analysis to investigate if there are other causes entire range including cell- and material level. The degradation in cell level is the inhomogeneous electrochemical reaction, that is within composite cathode, resulting from analysis of electrochemical impedance spectroscopy, cross-sectional scanning electron microscopy, x-ray diffraction, and X-ray photoelectron spectroscopy. This induces more severe degradation on close to SE separator, resulting in intensification of SE deterioration accompanied by damage implying a phase transformation of the active material. Furthermore, even though the contact loss problem has improved through re-pressing, the capacity was not recovered, which is because the material itself has deteriorated.Moving on to the material level, many cracks are observed inside of the active material, and sulfur infused into grain-boundary of active materials that confirmed by energy dispersive X-ray spectroscopy. In addition, through analyzing transmission electron microscopy, the phase transformation both mixed and rock-salt phase was confirmed the cathode surface of not only secondary particle but also primary particle of interior cathode. For more specifically affirmed this, various analysis including Raman spectroscopy and inductively coupled plasma optical emission spectroscopy were conducted, and we confirmed that the major cause is due to depletion of the Li source. Therefore, the loss of active Li by infused sulfur caused acceleration of deterioration cathode making poor capacity retention. This study is meaningful in providing another guideline that should be regarded for practical all-solid-state batteries through a new consideration in cathode degradation.

Electrochemical performance optimization of NMC811 through the structure design of its precursor

This paper presents a study on the effect of the precursor structure on NMC811 electrochemical properties. The influence of different parameters, such as morphology and crystallinity of the precursor, Ni0.8Mn0.1Co0.1(OH)2, on the final electrochemical performance of NMC811 are analyzed. To ensure a correct and fast mixing of the precursor reactants and prepare the Ni0.8Co0.1Mn0.1(OH)2, a novel approach is used employing a micromixer, thus enabling the collection of the precipitated metal hydroxide within a few seconds after its precipitation. Then the precursor is calcinated together with a Li source to obtain the NMC811 cathode material. When analyzing the aging time of the precursor, between collection and calcination, it is observed that the primary particles of the precursor grow and become more crystalline, adopting a lamellar shape, while the secondary particles turn more compact, when increasing the aging time. The NMC materials synthesized from the aged precursors have smoother primary particles, exposing clearer crystalline planes. This change in morphology is also evidenced in the crystalline structure where an increase in the aging time produces better layered materials with a lower cation mixing index. The well-ordered structure impacts the electrochemical characteristics; indeed, the aged precursor produces NMC with higher specific capacity, better cyclability and lower capacity fade.