Tuning Two Interfaces with Fluoroethylene Carbonate Electrolytes for High-Performance Li/LCO Batteries

Lee, Jin–Hong; Jin, Hyungyu; Noh, Hyungjun; Kwack, Hobeom; Chu, Hye Yong; Ye, Fangmin; Lee, Hongkyung; Kim, Hee‐Tak

doi:10.1021/acsomega.8b03022

Cited by 39 publications

(20 citation statements)

References 46 publications

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“…To characterize the SEI composition, X‐ray photoelectron spectroscopy (XPS) of the Li metal surfaces was conducted after 10 cycles of galvanostatic plating/stripping. In the O 1s spectra in Figure 4e, the COC bond peaks, which are related to the DME decomposition, [ 31 ] decreased evidently when increasing the LiNO 3 ratio. Since the solvent coordination on Li + solvation reduced with the NO 3 − addition, the direct contact of DME with Li metal was repressed, then its reductive decomposition was effectively suppressed throughout cycles.…”

Section: Resultsmentioning

confidence: 99%

Unraveling the Dual Functionality of High‐Donor‐Number Anion in Lean‐Electrolyte Lithium‐Sulfur Batteries

Chu

Jung

Noh

et al. 2020

Advanced Energy Materials

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104

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Despite the theoretically high energy density, the practical energy density of Li-S batteries at the moment does not meet the demand due to low sulfur (S) loading (<2 mg cm −2 ), large electrolyte amount (electrolyte/sulfur ratio >20 µL mg −1 ), and excess lithium (Li) metal use (>10 times excess). [5] In particular, large electrolyte usage (flooding) greatly diminishes the practical energy density of Li-S batteries. Due to the intrinsic solution-based redox chemistry, however, many of the challenges arise from minimizing the electrolyte/ sulfur ratio (E/S ratio). Since soluble lithium polysulfide (LiPS, Li 2 S x when 2 < x ≤ 8) intermediates are self-redox mediating, the decrease in the LiPS dissolution causes a sluggish sulfur conversion and high polarization. [6] Next, the morphology of lithium sulfide (Li 2 S) electrodeposition and the kinetics of the re-oxidation are affected by the sulfur species solubility as well. [7] Hence, uncontrolled precipitation and continual accumulation of Li 2 S limit the discharge capacity and further passivate the cathode interface throughout the cycling. [8] Reducing the electrolyte volume exacerbates not only the cathode performance but also the anode stability. A high reactivity and an infinite volume change of the Li metal anode cause the incessant decomposition of the electrolyte. Therefore, the lean electrolyte condition accelerates the increase of the cell resistance and provokes earlier performance failure compared to the flooding electrolyte system. [9] Manipulating electrolyte materials (solvents, salt anions, and additives) has a considerable impact on the electrochemical performance of Li-S batteries. There have been studies in which solvents with high Gutmann donor numbers (DNs) form strong interactions with lithium ions (Li + ) and promote the solvation of polysulfide (PS) anions. The increased LiPS solubility facilitates the solution-mediated reaction pathway, enabling fast reaction kinetics and high sulfur utilization. [10] Furthermore, the same merits can also be achieved with salt anions having high-DNs [11] or additives promoting ionic solvation. [12] Under a lean electrolyte regime, the role of highly solvating electrolytes becomes more prominent because of the limited solubility of sulfur species. For example, high-DN solvents can enhance the sulfur utilization under the reduced electrolyte amount by promoting the charge/discharge reactions. [13] Despite this fact, the Minimizing electrolyte use is essential to achieve high practical energy density of lithium-sulfur (Li-S) batteries. However, the sulfur cathode is more readily passivated under a lean electrolyte condition, resulting in low sulfur utilization. In addition, continuous electrolyte decomposition on the Li metal anode aggravates the problem, provoking rapid capacity decay. In this work, the dual functionalities of NO 3 − as a high-donor-number (DN) salt anion is presented, which improves the sulfur utilization and cycling stability of lean-electrolyte Li-S batteries. The NO 3 − anion eleva...

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Section: Resultsmentioning

confidence: 99%

Unraveling the Dual Functionality of High‐Donor‐Number Anion in Lean‐Electrolyte Lithium‐Sulfur Batteries

Chu

Jung

Noh

et al. 2020

Advanced Energy Materials

Self Cite

104

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“…The difference in the permeability of the binder layer to the electrolyte could also affect the onset potential of FEC decomposition. 76 Indeed, FEC has a large permittivity (ε r = 110) 77 and a highly charged binder layer such as for pH 6 could facilitate the passage of the electrolyte through this layer because of the dissociation of the lithium carboxylate groups. As a matter of fact, the ionization of the COO − −Li + bonds must facilitate the separation of the polymer chains via the electrostatic repulsion between the neighboring carboxylates and the swelling of the polymer layer by the electrolyte.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Influence of the Polyacrylic Acid Binder Neutralization Degree on the Initial Electrochemical Behavior of a Silicon/Graphite Electrode

Xiong

Dupré

Mazouzi

et al. 2021

ACS Appl. Mater. Interfaces

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The role of the physico-chemical properties of the water soluble PAA binder on the lithium electrochemical performance of highly loaded silicon/graphite 50/50 wt% negative electrodes has been examined as a function of the neutralization degree x in PAAH1-xLix at initial cycle in an electrolyte not-containing ethylene carbonate. Electrode processing in acidic PAAH binder at pH 2.5 leads to a deep copper corrosion resulting in a significant electrode cohesion and adhesion to the current collector surface, but the strong binder rigidity may explain the big cracks occurring at the electrode surface at first cycle. The non-uniform binder coating on the materials surface leads to an important degradation of the electrolyte explaining the lowest initial coulombic efficiency and the lowest reversible capacity among the studied electrodes. When processed in neutral pH, the PAAH0.22Li0.78 binder forms a conformal artificial SEI layer on the materials surface, which minimizes the electrolyte reduction at first cycle and then maximizes the initial coulombic efficiency. However, the low mechanical resistance of the electrode and its strong cracking explain its low reversible capacity. Electrodes prepared at intermediate pH 4 combine the positive assets of electrodes prepared at acidic and neutral pH. They lead to the best initial performance with a notable areal capacity of 7.2 mAh cm -2 and the highest initial coulombic efficiency at around 90%, a value much larger than the usual range reported for silicon/graphite anodes. All data obtained with complementary characterization techniques were discussed as a function of the PAA polymeric chain molecular conformation, microstructure, and surface 3 adsorption or grafting, emphasizing the tremendous role of the binder on the electrode initial performance.

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“…Furthermore, the use of suitable additives remarkably enhanced the electrode passivation behavior, leading to promising cell performances. Indeed, literature works have shown that vinylene carbonate (VC), fluoroethylene carbonate (FEC), and lithium nitrate (LiNO 3 ) may improve the SEI between anode and electrolyte. In particular, it is widely demonstrated that LiNO 3 ‐containing electrolytes may form a uniform and stable anode passivation layer containing both organic ( e.g ., ROLi and ROCO 2 Li) and inorganic ( e.g ., Li x NO y , Li 3 N, and Li 2 O) species, which can mitigate the parasitic reactions in the cell and limit the lithium dendrite growth .…”

Section: Introductionmentioning

confidence: 99%

Towards a High‐Performance Lithium‐Metal Battery with Glyme Solution and an Olivine Cathode

et al. 2020

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High‐performance lithium‐metal batteries are achieved by using a glyme‐based electrolyte enhanced with a LiNO3 additive and a LiFePO4 cathode. An optimal electrolyte formulation is selected upon detailed analysis of the electrochemical properties of various solutions formed by dissolving respectively lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(pentafluoroethanesulfonyl)imide (LiBETI) either in diethylene glycol dimethyl ether or in triethylene glycol dimethyl ether and by adding LiNO3. A thorough investigation shows evidence of efficient ionic transport, a wide stability window, low reactivity with lithium metal, and cathode/electrolyte interphase characteristics that are strongly dependent on the glyme chain length. The best Li/LiFePO4 battery delivers 154 mAh g−1 at C/3 (1 C=170 mA g−1) without any decay after 200 cycles. Tests at 1 C and 5 C show initial capacities of about 150 and 140 mAh g−1, a retention exceeding 70 % after 500 cycles, and suitable electrode/electrolyte interphases evolution.

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Tuning Two Interfaces with Fluoroethylene Carbonate Electrolytes for High-Performance Li/LCO Batteries

Cited by 39 publications

References 46 publications

Unraveling the Dual Functionality of High‐Donor‐Number Anion in Lean‐Electrolyte Lithium‐Sulfur Batteries

Unraveling the Dual Functionality of High‐Donor‐Number Anion in Lean‐Electrolyte Lithium‐Sulfur Batteries

Influence of the Polyacrylic Acid Binder Neutralization Degree on the Initial Electrochemical Behavior of a Silicon/Graphite Electrode

Towards a High‐Performance Lithium‐Metal Battery with Glyme Solution and an Olivine Cathode

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