Li Species Research Articles

Ultrasonic pretreatment of spodumene with different size fractions and its influence on flotation

The potential of ultrasonic pretreatment enhancing selective surface dissolution to improve the floatability of spodumene with different size fractions was verified and investigated. For coarse particles of −0.15 + 0.0385 mm, compared with traditional pretreatment methods, ultrasonic pretreatment could optimize the physicochemical properties of the surface, markedly increased the amount of NaOL adsorbed on the mineral surface, and improved the floatability of the spodumene. For fine particles of −0.0385 mm, both pretreatment methods (Ultrasonic and Traditional) could greatly increase the flotation recovery, but ultrasonic pretreatment had no obvious advantage compared with traditional method. ICP combined with XPS analysis were conducted to investigate the dissolution mechanism of spodumene surface in different pretreatment system. Si species on the surface of coarse particles were easily dissolved into the solution under the effect of ultrasound, which increases the relative content of Al and Li species on the surface. This was conducive to the adsorption of the collectors on the surface. However, the selective dissolution of the fine particle surface was weakened by excessive energy intake in the ultrasonic system, which neutralized the advantage brought by the large amount of dissolution, making the results obtained by the two preprocessing methods the same.

Quantitatively analyzing the failure processes of rechargeable Li metal batteries.

Practical use of lithium (Li) metal for high–energy density lithium metal batteries has been prevented by the continuous formation of Li dendrites, electrochemically isolated Li metal, and the irreversible formation of solid electrolyte interphases (SEIs). Differentiating and quantifying these inactive Li species are key to understand the failure mode. Here, using operando nuclear magnetic resonance (NMR) spectroscopy together with ex situ titration gas chromatography (TGC) and mass spectrometry titration (MST) techniques, we established a solid foundation for quantifying the evolution of dead Li metal and SEI separately. The existence of LiH is identified, which causes deviation in the quantification results of dead Li metal obtained by these three techniques. The formation of inactive Li under various operating conditions has been studied quantitatively, which revealed a general “two-stage” failure process for the Li metal. The combined techniques presented here establish a benchmark to unravel the complex failure mechanism of Li metal.

Etching mechanism of LiTaO3 crystals in CHF3/Ar plasma

CHF3/Ar plasma was used to etch LiTaO3 crystal by inductively coupled plasmas technique. X-ray photoelectron spectroscopy was performed to investigate the etching mechanism. It was found that chemical reactions had occurred between the F plasma and the Li and Ta metal species, forming the corresponding fluorides. Some fluorides are nonvolatile, and remained on the surface during the etching period. In order to get higher etching rate, it is important to remove these metal fluorides. The combination of chemical reaction and sputtered etching was performed and could effectively remove the remaining residues.

Multimodal Characterization of Degradation Mechanisms in Lithium-Ion Batteries from Extreme Fast Charging

Electric vehicles (EVs) powered by Li-ion batteries (LIBs) continue to gain prominence in comparison to traditional gasoline-powered vehicles. A major and immediate area of improvement for current LIBs used in EVs is to decrease the recharging time, in order to make it comparable to traditional refueling times. To this end, a sub-15 minute recharging time has been identified as an immediate target to achieve, called extreme fast charging (XFC) [1]. However, XFC of LIB is associated with safety and performance issues. Safety issues during XFC cycling can result from irreversible Li plating on the anode, which can lead to a short between the electrodes [2]. Two major pathways for capacity loss in LIBs over cycling are (i) depletion of the recyclable lithium inventory in the cell and (ii) the loss of sites on the active material (electrodes) [3]. Thus, an in-depth of understanding of the mechanisms of irreversible capacity loss including characterization of individual lithium loss mechanisms and the extent of electrode degradation, as well as the conditions that cause it hold the key to designing the next generation of XFC-capable LIBs.In this work, we employ a combination of sub-mm-scale in-situ high-energy x-ray diffraction (XRD) and ex-situ mass spectrometry titration (MST) to quantify the various loss mechanisms in LIBs from XFC cycling. XRD is used to furnish local information on the spatial heterogeneity of loss of lithium inventory (through mechanisms such as irreversible Li plating) and loss of active electrode material, as well as the contribution of such mechanisms to the global cell performance. MST is used to quantify the exact amounts of loss of lithium inventory over the entire cell (such as plated Li, Li-carbonate and Li-acetylide species). The end-of-life characterizations are conductedafter 450 XFC cycles, on single layer pouch cells (3 mAh/cm2 specific capacity, with graphite anode and NMC cathode), where the charging rate and protocol are systematically varied (4C to 9C). The experiments reveal that irreversible lithium plating and electrolyte oxidation/reduction reactions at either electrode are the primary contributions to XFC capacity fade. Dead lithiated graphite species that are co-located with the irreversibly plated lithium constitute a minor component of the capacity fade. Additionally, even though a loss of active electrode material is seen in the cells, the cell capacity is completely dictated by the loss of recyclable lithium ions. Such anapproach emphasizes the importance of multimodal, multiscale characterizations in understanding degradation pathways in LIBs, in order to design the next generation of XFC capable batteries.

Following the Lithium: Tracing Li-bearing Molecules across Age, Mass, and Gravity in Brown Dwarfs

Abstract Lithium is an important element for the understanding of ultracool dwarfs because it is lost to fusion at masses above ∼68 M J. Hence, the presence of atomic Li has served as an indicator of the nearby H-burning boundary at about 75 M J between brown dwarfs and very low mass stars. Historically, the “lithium test,” a search for the presence of the Li line at 670.8 nm, has been a marker if an object has a substellar mass. While the Li test could, in principle, be used to distinguish masses of later-type L–T dwarfs, Li is predominantly no longer found as an atomic gas but rather a molecular species such as LiH, LiF, LiOH, and LiCl in cooler atmospheres. The L- and T-type dwarfs are quite faint at 670 nm and thus challenging targets for high-resolution spectroscopy. But only recently have experimental molecular line lists become available for the molecular Li species, allowing molecular Li mass discrimination. Here we generated the latest opacity of these Li-bearing molecules and performed a thermochemical equilibrium atmospheric composition calculation of their abundances. Finally, we computed thermal emission spectra for a series of radiative–convective equilibrium models of cloudy and cloudless brown dwarf atmospheres (with T eff = 500–2400 K and log g = 4.0 – 5.0 ) to understand where the presence of atmospheric lithium-bearing species is most easily detected as a function of brown dwarf mass and age. After atomic Li, the best spectral signatures were found to be LiF at 10.5–12.5 μm and LiCl at 14.5–18.5 μm. Also, LiH shows a narrow feature at ∼9.38 μm.

Lithium/bismuth co-functionalized phosphotungstic acid catalyst for promoting dinitrogen electroreduction with high Faradaic efficiency

Ammonia occupies a significant standing in the global economy. As a promising alternative to the energy-intensive Haber-Bosch process, electrochemical nitrogen reduction could achieve sustainable ammonia synthesis. However, the attractive alternative suffers from the bottleneck of insufficient activity and low electron selectivity. Here, we report an efficient electrocatalyst using phosphotungstic acid as platforms to anchor bismuth species on the 4-fold hollow site and anchor lithium species on the 3-fold hollow site, which reaches high ammonia yield rates of 61 ± 1 μg h −1 mg cat. −1 and Faradaic efficiencies of 85% ± 2% at −0.1 V versus reversible hydrogen electrode (RHE). Experiments and theoretical calculations reveal that the Bi δ+ species can promote the activation and hydrogenation of nitrogen at adjacent unsaturated tungsten active sites, and the incorporated lithium species reduce the hydrogen reduction rate in undesired water splitting. This synergistic functionalization of bismuth and lithium species contributes to the high-efficient catalyst. Li/Bi species are anchored on phosphotungstic acid by impregnation Li/Bi species synergistically contribute to the activation of nitrogen Li species are favorable to inhibit the competitive hydrogen evolution reaction Li/Bi species teamwork achieves a high Faradic efficiency for aqueous ammonia synthesis Electrochemical nitrogen reduction could achieve sustainable ammonia synthesis as a promising alternative to the energy-intensive Haber-Bosch process. Liao et al. design Li/Bi co-functionalized phosphotungstic acid by precisely anchoring Bi and Li species, where Bi δ+ species facilitate nitrogen reduction and Li species suppress competitive hydrogen evolution reaction. The cooperation promotes electrocatalytic nitrogen reduction to ammonia with, to the best of our knowledge, record Faradic efficiencies for aqueous systems.

A novel approach to prepare Li-La-Zr-O solid state electrolyte films by suspension plasma spray

In this work we investigated a novel approach to prepare Li-La-Zr-O solid-state electrolyte films by the suspension plasma spray process. This process offers several advantages that make it a promising low-cost, rapid and robust production method for garnet-type Li-ion conductors. A cubic garnet-type, Li6.75La3Zr1.75Nb0.25O12, ethanol-based suspension was plasma sprayed on stainless-steel substrates using two torch power levels, 30.9 and 77.1 kW, at different stand-off distances. Solid-state electrolyte films of ~14 μm thickness were deposited in ~0.1 h of spraying. Maximum Li-ion conductivity as high as 7.3·10−6 S cm−1 at 22 °C has been obtained for the samples sprayed at 30.9 kW and stand-off distance of 25 mm. These samples contained a majority of amorphous phase (67.0 wt%), 20.2 wt% of Li6.75La3Zr1.75Nb0.25O12, and the balance of 12.8 wt% of the pyrochlore phase (La2Zr2O7). We associate this result with the relatively high value of Li number density, 2.2·1022 cm−3, and the lowest content of La2Zr2O7. The higher torch power level and/or longer stand-off distance leads to a reduction in Li number density and higher content of La2Zr2O7, likely due to evaporative loss of Li species during the spray process. These factors also translate to a decrease in Li-ion conductivity. The knowledge that has been acquired in this preliminary study provides guidelines for further development and optimization of this rapid deposition technique of garnet-type solid-state electrolyte films.

Bio-inspired construction of ion conductive pathway in covalent organic framework membranes for efficient lithium extraction

Summary As the most sophisticated separation system, biological membranes have served as natural prototypes for the design of artificial membranes because they provide high permeability and solute selectivity, owing to the presence of specialized ion channels. However, developing stable and selective artificial ion channels remains a formidable challenge. Herein, we demonstrate the construction of lithium nanochannels in two-dimensional covalent organic frameworks (COFs) to create biomimetic membranes. Implanted lithiophilic oligoethers conferred specificity and facilitated Li+ diffusion along the pore pathway of the COF. The ion channel characteristics were indicated by reversal potential measurements, showing that the relative permeability decreased in the order Li+ > K+ > Na+ > Ca2+ > Mg2+. The Li+ transfer was enhanced, while other ions were obstructed, allowing for high selectivity and permeability. A Li+/Mg2+ separation factor of 64 was achieved, confirming high lithium affinity. This study may serve as a design principle to develop selective artificial membranes for effective ion separation.

(tBuN)SiMe2NMe2—A new N,N′-κ2-monoanionic ligand for atomic layer deposition precursors

Eight new atomic layer deposition (ALD) precursors were synthesized using a ligand that is new to the field of ALD: (tBuNH)SiMe2NMe2. Complexes containing Mg, V, Mn, Fe, Co, Ni, and Zn were found to be tetrahedral, and Li complexes form more complex structures. These compounds performed exceptionally well by thermogravimetric analysis (TGA). All compounds except for one Li species and the Fe complex left residual masses below 5%, similar or better than the analogous amidinate complexes. In particular, the Co(II) complex is very thermally robust and performs very well during a TGA stress test, surpassing temperatures above 200 °C. These compounds are the first of a family of precursors containing this type of monoanionic N–Si–N ligand and are prime candidates for ALD process development.

Valorization of glycerol into glycerol carbonate using the stable heterogeneous catalyst of Li/MCM-41

The present study explored the catalytic activity of the heterogeneous catalyst for transesterification of glycerol into glycerol carbonate, a versatile compound. Transesterification of glycerol was investigated with different active metals (Li, La, Ce, Mg, K) impregnated on MCM-41 (Mobil Composition of Matter No. 41) framework. Among these, lithium incorporated MCM-41 proved the better catalytic activity towards the formation of glycerol carbonate. The shortening of a long-range hexagonal array was observed with active metal incorporation due to the accumulation of non-framework Li species in the MCM-41 structure. BET study revealed that Li/MCM-41 possess type IV hysteresis loop according to IUPAC standards. The average pore diameter was increased from 25.43 Å to 62.02 Å with active metal incorporation in the MCM-41 framework. The catalytic activity of Li/MCM-41 was observed by varying different weight ratios of active metal and the calcination temperature. The results demonstrated that 5 wt% Li impregnated on MCM-41, calcined at 450 °C, appeared to have a maximum yield of glycerol carbonate. Additionally, the influence of reaction operating parameters was also investigated. The results showed that 99 ± 1.89% glycerol conversion and 93.14 ± 2.52% glycerol carbonate yield was achieved at dimethyl carbonate-to-glycerol molar ratio of 3, catalyst dosage of 4 wt% (relative to glycerol mass) and a reaction temperature of 90 °C in 3 h. The recyclability and stability of the screened catalyst was also studied under optimized conditions. The activation energy of the catalyst was determined by solving the differential equation using MATLAB ODE15s tool, and the obtained value was 53.77 ± 3.26 kJ/mol. The E-factor and PMI (Process mass intensity) values of glycerol carbonate synthesis were determined as 1.16 and 2.16, respectively, which demonstrate the less waste generation during the process.

A parallel-plate RF probe and battery cartridge for 7Li ion battery studies

A new parallel-plate resonator for 7Li ion cell studies is introduced along with a removable cartridge-like electrochemical cell for lithium ion battery studies. This geometry separates the RF probe from the electrochemical cell permitting charge/discharge of the cell outside the magnet and introduces the possibility of multiplexing samples under test. The new cell has a geometry that is similar to that of a real battery, unlike the majority of cells employed for MR/MRI studies to this point. The cell, with electrodes parallel to the B1 magnetic field of the probe, avoids RF attenuation during excitation/reception. The cell and RF probe dramatically increase the sample volume compared to traditional MR compatible battery designs. Ex situ and in situ 1D 7Li profiles of Li ions in the electrolyte solution of a cartridge-like cell were acquired, with a nominal resolution of 35 µm at 38 MHz. The cell and RF probe may be employed for spectroscopy, imaging and relaxation studies. We also report the results of a T1-T2 relaxation correlation experiment on both a pristine and fully charged cell. This study represents the first T1-T2 relaxation correlation experiment performed in a Li ion cell. The T1-T2 correlation maps suggest lithium intercalated into graphite is detected by this methodology in addition to other Li species.

Synergistic Functionalization for Promoting Dinitrogen Electroreduction with High Faradaic Efficiency

Electrochemical nitrogen reduction is suffering from the bottleneck of poor activity and low electron selectivity. Herein, we precisely synthesize an efficient electrocatalyst using phosphotungstic acid as a platform to anchor Bi species on the four-fold hollow site and associate with Li species on the three-fold hollow site. The well-designed catalyst shows a significant eNRR performance with an ammonia yield rate of 61 ± 1 μg h-1 mgcat.-1 and a recorded Faradaic efficiency of 85 ± 2% at -0.1 V vs. RHE. Isotopic labeling verifies that N atoms of formed NH4+ originate from N2. In situ experiments and theoretical calculations reveal that the Biδ+ species could promote the effective activation and hydrogenation of dinitrogen molecules at the adjacently unsaturated W active sites, and the incorporated Li species reduce the hydrogen reduction rate in the undesirable water splitting. This synergistic functionalization of Bi and Li species contributes to the high-efficient catalyst.

Quantification of Inactive Lithium, Solid Carbonate Species, and Lithium Acetylide on Graphite Electrodes after Fast Charging

Lithium plating on graphite anodes currently limits the fast charging performance of lithium-ion batteries because plated Li is prone to become electronically isolated from the electrode (referred to as 'inactive Li') or react with electrolyte, both of which contribute to rapid cell capacity fade. To understand the onset and extent of these detrimental processes, it is critical to quantify these sources of capacity loss. In this work, we demonstrate a titration technique to quantify both inactive Li and solid electrolyte interphase (SEI) species (solid carbonates and lithium acetylide, Li2C2) that remain on the graphite electrode after fast charging. We additionally compare electrochemical modeling results with our experimental data to determine the Li plating exchange current density (10 A/m2) and stripping efficiency (65%) of plated Li metal on graphite. Our techniques lay the groundwork for benchmarking proposed Li plating detection techniques and provide an avenue to pursue more comprehensive studies of Li plating on graphite surfaces.

Numerical simulation of Li-pellet injection experiments for ELM-pacing in EAST

The injection of light impurity granules into fusion research discharges has shown a great potential for ELM pacing in future nuclear devices. The present work employed a model considering both pellet ablation and transport to systematically study for the first time the evolution of both impurity Li species and target plasma in the edge plasma during single and repeated Li pellet injections, with all initial information extracted from the EAST experiments. The evolutionary distributions of atomic and ionized Li species were presented and show good consistency with experimental CCD camera images. Simulation studies were carried out for single and repeated pellet injections at the outer mid-plane, and statistical uncertainty of ELM pacing rates triggering ELMs is discussed with regard to related injection conditions. It is found that the pressure locally caused by an ELM pacing pellet (with a diameter of 0.6 ∼ 0.7 mm) was 1.8–2.4 times its unperturbed magnitude in the EAST shots of interest. Accumulation from repeated pellet injections results in the rise of pedestal height at a high injection frequency and this effect becomes stronger with increasing pellet size. Pressure changes are also evident in a scenario of multiple small pellets per stroke, which could lead to a nonnegligible, probabilistic ELM triggering rate observed experimentally. The effects of other possible factors are also discussed. With the assumption that the ELM trigger rate of a Li pellet of 0.7 mm diameter is 100%, the predicted trigger rates are in good agreement with those observed in experiments. This work can help understand the statistically probabilistic behavior of ELM triggering efficiency observed in previous studies.

Ultra-fast construction of plaque-like Li2TiO3/TiO2 heterostructure for efficient gas-solid phase CO2 photoreduction

Exploring a facile and universal strategy to fabricate an efficient heterostructure is a big challenge for achieving highly active and selective CO2 photoreduction. Herein, a plaque-like Li2TiO3/TiO2 heterostructure was in-situ constructed by the gradual intercalation of Li ions into the lattice of TiO2 from the outside and eventually formed the Li2TiO3 phase on the surface of TiO2 in an ultra-high temperature about 2000 K within several milliseconds. This novel structure has a significant improvement in the adsorption capacity of CO2 and reduction of the oxygen defect trap by introduction of Li species. Furthermore, owing to the built-in electric field directed from Li2TiO3 to TiO2, electrons are forced to move to the oxygen atom sites in Li2TiO3, which helps the plaque-like Li2TiO3/TiO2 heterostructure photocatalyst achieve nearly 3 times performance improvement with about 100 % selectivity towards CO. Theoretically and experimentally, we proposed a possible catalytic behavior and mechanism that Li2TiO3/TiO2 heterostructure will choose a shorter pathway through intermediate formate conversion to CO, as the free energy reduce by 26.53 % from 0.98 eV to 0.72 eV. This work gives a new insight for constructing heterostructure in an ultra-fast reaction process, and provides a rational reference for developing highly efficient photocatalysts towards CO2 reduction.

Hydrophobic strong solid base derived from graphene oxide hybrid zirconium MOFs and its enhanced stability on furfural-MIBK aldol condensation to synthesize branched biofuel precursors

Aldol condensation between furfural (FA) and MIBK is used to synthesize branched bio-jet-fuel precursors. It remains difficult to design hybrid solid bases to efficiently promote this reaction, because only strong basic sites can activate MIBK. Different basic species were immobilized into zirconia/carbon hybrid supports by thermal decomposition of GO/UiO materials loaded with corresponding alkane (earth) nitrides. Only Cs immobilized zirconia/carbon (CsZC) could efficiently promote this reaction, while counterparts with Li, Mg and Ca species showed little activity over condensation between MIBK and FA. Optimized CsZC showed excellent FA conversion and selectivity towards desired products (88.6% in yields of FMIBK in 6 h at 130 °C). Two indirect proofs were provided to check the influence of basic strength on the catalytic performance, and only Cs samples had enough strong basic sites to accelerate the reaction. After modified with octyl groups, hydrophobic CsZC were reused for 4th cycle while retaining most of its original activity. Functionalization with organosilanes increased the hydrophobicity of the surface, which had dramatical promotion on activity, selectivity, and stability. It was the first time to run recycling experiments for this reaction, to afford the demands for chemical sustainability.

Unveiling Lithium Roles in Cobalt‐Free Cathodes for Efficient Oxygen Reduction Reaction below 600 °C

AbstractImproving the sluggish electrocatalytic oxygen reduction reaction (ORR) over cobalt‐free cathodes at 550–800 °C is imperative to circumvent challenges faced by practical operation of intermediate temperature solid oxide fuel cells. In this work, we synthesize novel cobalt‐free, lithium (Li)‐doped, perovskite oxides Sr1‐xLixFe0.8Nb0.1Ta0.1O3‐δ (SLFNTx, x=0–0.1) as cathodes for efficient ORR catalysis. When the Li concentration is less than 0.05, ORR activity is enhanced by over 1.6‐fold in comparison to the undoped SFNT below 600 °C in both symmetrical and anode‐supported single cells configurations. Our comprehensive investigation over crystal structure, surface, and mixed conductivities revealed that a moderate concentration (<0.05) of Li could bestow the perovskite with a stable cubic perovskite structure that contains an optimal concentration of oxygen vacancies and A‐site deficiencies. Such trend originates from the lower electronegativity and smaller size of Li dopant than the strontium host. The lower electronegativity increases oxygen vacancies. The small Li dopant induces thermal‐migration of Li species and creates A‐site deficiency. These insights highlight an effective strategy to advance the performance of cobalt‐free ORR electrocatalyst below 600 °C through in situ thermal surface migration of the A‐site cations.

Mechanism of Li storage on graphene nanoflakes: Density functional theory study

The efficiency of metal storage in carbon materials directly affects battery performance. Therefore, elucidating the storage mechanism is important for developing high-efficiency and new storage materials. In this study, interatomic interactions between Li species (Li atoms and Li+ ions) and graphene nanoflakes (GRs) have been investigated using the density functional theory method to elucidate the mechanism of Li storage on GRs. Moreover, single, double, and triple Li species were examined. For single Li systems (n = 1), the binding energy and diffusion barrier of Li on GRs were investigated, while the interatomic interactions and packing structures of Li species on GRs were investigated for double and triple Li systems (n = 2 and 3, respectively). The diffusion barriers for Li+ and Li for n = 1 were calculated to be 5.90 and 6.84 kcal/mol, respectively. For n = 2, the diffusion was strongly affected by the counter Li species and was attributed to the repulsive interactions. For n = 2, the close packing configurations of Li species on the surface of the GRs consisted of biphenyl structures where Li species were located inside the benzene rings of the biphenyl-like site of GRs. For n = 3, three Li species were bound to the triphenylene sites (two biphenyl-like sites). The electronic states of the Li species stored on GRs were discussed using the theoretical results.

(Invited) Operando Analysis for Charge/Discharge Reaction Mechanism of Graphite Anode of Li Ion Battery

The first preparation of Li-graphite intercalation compound (Li-GIC) was attempted by Hérold et al. in 1955. Since then, a lot of reports have been made mainly by the research groups in France, and with regard to the stage I and II compounds, it is clarified that they take the in-plane structures called by P(√3×√3)R30°. Though there have been many reports since 1970s, the detail discussion has not been done so far concerning the intercalation mechanism and in-plane structure of higher stage compounds. The first reason is that the concentration of Li species becomes smaller in the higher stages. The second reason is the strong preferred orientation of graphite. Such reasons make difficult to clarify the intercalation mechanism and in-plane structure. In order to improve the performance of Li-ion battery, it is essential to investigate the detail structure change of graphite electrode during the charge/discharge process. In this study, in order to elucidate the intercalation mechanism and structure change not only along c-axis, but also along the a,b-axes, we traced dynamically the intercalation reaction in Li-ion battery negative electrode by Operando measurement with synchrotron radiation diffraction.

Efficient Li-Metal Plating/Stripping in Carbonate Electrolytes Using a LiNO3-Gel Polymer Electrolyte, Monitored by Operando Neutron Depth Profiling

The development of safe and high-performance Li-metal anodes is crucial to meet the demanded increase in energy density of batteries. However, severe reactivity of Li metal with typical electrolytes and dendrite formation leads to a poor cycle life and safety concerns. Therefore, it is essential to develop electrolytes that passivate the reactivity toward Li metal and suppress dendrite formation. Carbonate electrolytes display severe reactivity toward Li metal; however, they are preferred above the more volatile ether-based electrolytes. Here, a carbonate electrolyte gel polymer approach is combined with LiNO3 as an additive to stabilize Li-metal plating. This electrolyte design strategy is systematically monitored by operando neutron depth profiling (NDP) to follow the evolution of the plated Li-metal density and the inactive lithium in the solid electrolyte interface (SEI) during cycling. Individually, the application of the LiNO3 electrolyte additive and the gel polymer approach are shown to be effective. Moreover, when used in conjunction, the effects are complementary in increasing the plated Li density, reducing inactive Li species, and reducing the overpotentials. The LiNO3 additive leads to more compact plating; however, it results in a significant buildup of inactive Li species in a double-layer SEI structure, which challenges the cell performance over longer cycling. In contrast, the gel polymer strongly suppresses the buildup of inactive Li species by immobilizing the carbonate electrolyte species; however, the plating is less dense and occurs with a significant overpotential. Combining the LiNO3 additive with the gel polymer approach results in a thin and homogeneous SEI with a high conductivity through the presence of Li3N and a limited buildup of inactive Li species over cycling. Through this approach, even high plating capacities, reaching 7 mAh/cm2, can be maintained at a high efficiency. The rational design strategy, empowered by monitoring the Li-density evolution, demonstrates the possibilities of achieving stable operation of Li metal in carbonate-based electrolytes.