Surface Characterization of the Carbon Cathode and the Lithium Anode of Li–O<sub>2</sub> Batteries Using LiClO<sub>4</sub> or LiBOB Salts

Younesi, Reza; Hahlin, Maria; Edström, Kristina

doi:10.1021/am3026129

Cited by 66 publications

(72 citation statements)

References 44 publications

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“…The rechargeable Li-O 2 battery has recently attracted a great deal of attention because of its significantly higher theoretical energy density than traditional lithium-ion battery [1][2][3][4][5]. A Li-O 2 battery prototype is composed of a lithium metal anode, Li + -containing nonaqueous electrolyte, and a porous O 2 cathode (normally carbon-based materials with or without catalysts).…”

Section: Introductionmentioning

confidence: 99%

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

Liu

Wang

Zhu

2016

Journal of Power Sources

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This work presents a novel binder-free nitrogen-doped carbon paper electrode (NCPE), which was derived from a N-rich polypyrrole (PPy)/cellulose-chopped carbon filaments (CCFs) composite, for Li-O 2 batteries. The fabrication of NCPE involved cheap raw materials (e.g., Cladophora sp. green algae) and easy operation (e.g., doping N by a carbonization of N-rich polymer), which is especially suitable for large-scale production. Asprepared NCPEs were characterized by XRD, Raman, SEM, XPS, Brunauer-Emmett-Teller (BET), and thermogravimetry (TG) measurements. The NCPE exhibited a bird's nest microstructure, which could provide the self-standing electrode with considerable mechanic durability, fast Li + and O 2 diffusion, and enough space for the discharge product deposition. In addition, the NCPE contained N-containing function groups, which may promote the electrochemical reactions. Furthermore, binder-free architecture designs can prevent binderinvolved parasitic reactions. A Li-O 2 cell with the NCPE dispalyed a cyclability of more than 30 cycles at a constant current density of 0.1 mA/cm 2 . The 1 st discharge capacity for a cell with the NCPE reached 8040 mAh· g -1 at a current density of 0.1 mA/cm 2 , with a cell voltage around 2.81 V. In addition, a cell with the NCPE displayed a coulombic efficiency of 81 % on the 1 st cycle at a current density of 0.2 mA/cm 2 . These results represent a promising progress in the development of a low-cost and versatile paper-based O 2 electrode for Li-O 2 batteries.

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Section: Introductionmentioning

confidence: 99%

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

Liu

Wang

Zhu

2016

Journal of Power Sources

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“…For example, Younesi et al reported the formation of carbonate and ether containing species on carbon electrode when cycling Li-O 2 batteries containing carbonate-based electrodes. 20 The chemical composition of the interface may further be semi-quantitatively evaluated, thus permitting a comparison between electrodes recovered after different cycling conditions.The aim is to study the complex surface electrochemistry of one of the most typical positive electrode material (nanoparticulate carbon Super C65) and electrolyte (0.2 M LiTFSI in Diglyme) combinations for Li-O 2 batteries by performing in situ gaseous, ex situ structural, morphological and compositional analysis during the first discharge/charge cycle. …”

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confidence: 99%

mentioning

confidence: 99%

XPS Study of the Interface Evolution of Carbonaceous Electrodes for Li-O₂Batteries during the 1st Cycle

Guéguen

Novák

Berg

2016

J. Electrochem. Soc.

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The surface chemistry of the commonly employed positive electrode substrate Super C65 carbon was investigated during the 1 st cycle of a Li-O 2 battery with a typical ether electrolyte (0.2 M LiTFSI in Diglyme) by performing in situ online electrochemical mass spectrometry (OEMS), ex situ scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). During discharge, a nanometer-thin (< 5 nm) layer of Li 2 O 2 forms homogeneously throughout the electrode before it is passivated at a final specific charge of ∼365 mAh/g. Higher discharge charge rates lead to thinner and more densely packed layers of Li 2 O 2 . Electrolyte decomposition also occurs in parallel, as evidenced by the continuous increase of LiF and sulfur containing species of the degraded LiTFSI salt. On charge, O 2 evolves initially according to a 2e − /O 2 rate, but as the cell over-potentials increase, O 2 evolution rate approaches 4e − /O 2 , thus demonstrating a significant extent of parasitic side-reactions. Unlike the discharge, the charge leads to inhomogeneous electrode reactions causing a continuous removal of Li 2 O 2 with no indication of LiO 2 or Li 2 O intermediates. The decomposition side-products formed during discharge are also removed and the spectra of the pristine electrode are nearly retained at a full charge. Our results show that the analysis of Li-O 2 battery chemistry requires broad approach based on the combination of various electrode surface sensitive techniques, such as XPS and OEMS, in order to provide further fundamental understanding of the mechanisms behind the complex electrochemistry involving the Li and O 2 as well as several other predominant degradation products of the electrode and electrolyte. Non-aqueous electrolyte based Li-O 2 batteries have been a subject of intensive research during the past years, mainly because of their high theoretical specific charge (∼1100 mAh/g Li2O2 ), which provide promising prospects for their implementation in future energy storage systems.1 Several challenges do however remain, of which the most notable are the low round-trip efficiency and poor cycling performance, both partly related to the electrode/electrolyte instability.2,3 On discharge of the Li-O 2 cell, gaseous oxygen dissolves in the electrolyte and is reduced at the positive porous electrode where it combines with Li + (from the negative Li metal electrode) to form solid Li 2 O 2 deposits according to forward reaction of 2Li + O 2 Li 2 O 2 . Upon charge, the reaction is reversed to release the initial reactants Li + and O 2 gas. Despite extensive research on several classes of electrodes and electrolytes (including carbons, gold, carbides, oxides substrates combined with carbonate, sulfoxide, [4][5][6] nitrile, 4,5,7 amide, ionic liquid 8,9 or ether 10-13 based electrolytes, to mention a few), no composition has so far displayed sufficient chemical stability toward the reduced oxygen species to sustain a satisfactory number of discharge/charge cycles.1 The cell failure has been...

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“…However, carbonate solvents have been shown to have unstable cathode and anode performance. [8][9][10][11][12] Research into ether based solvents was initially more promising with the formation of Li 2 O 2 clearly demonstrated.13,14 However, sustained stable cycling has not been conclusively established. [15][16][17] This combined with the instability of ethers to Li 2 O 2 as well as auto-oxidation reactions suggests that this solvent system is also unrealistic.…”

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confidence: 99%

Increased Cycling Efficiency of Lithium Anodes in Dimethyl Sulfoxide Electrolytes For Use in Li-O2 Batteries

Roberts

Younesi

Richardson

et al. 2014

ECS Electrochemistry Letters

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High lithium cycling efficiencies are required if a metal anode system is to be considered for use in Li-O 2 batteries. In this work electrolyte additives (0.3 M LiNO 3 and 0.14 M VC) were used to increase the efficiency from 25 to 82.5% in the topical DMSO based electrolyte. Furthermore, we show that oxygen also acts to improve the cycling efficiency to 87%. This work highlights the importance of anode considerations in the development of metal O 2 batteries in alternative solvents (DMSO, Acetonitrile and DMA) and suggests realistic strategies for performance improvements. The goal of a rechargeable Li-O 2 battery has stimulated many research studies in recent years. Practical estimates suggest that this system could provide a 2 to 5 times increase in energy density over current technologies.1-3 Ideal systems reduce oxygen during discharge (oxygen reduction reaction; ORR) forming of Li 2 O 2 which precipitates in the cathode architecture. Then on charging oxidize the Li 2 O 2 to form oxygen gas and lithium ions (oxygen evolution reaction; OER). The majority of studies have focused on lithium metal as the negative electrode (exceptions are silicon 4 or LiFePO 4 5 validation studies); here lithium metal is oxidized during discharge to form Li ions in solution which are then reduced back to metallic lithium on charge. The development of Li-O 2 batteries has been hampered by difficulties finding a stable electrolyte which allows these reactions to occur without accompanying decomposition.1,2,6,7 Many solvent systems have been investigated; with the majority of focus being on carbonates and ethers. However, carbonate solvents have been shown to have unstable cathode and anode performance. [8][9][10][11][12] Research into ether based solvents was initially more promising with the formation of Li 2 O 2 clearly demonstrated.13,14 However, sustained stable cycling has not been conclusively established. [15][16][17] This combined with the instability of ethers to Li 2 O 2 as well as auto-oxidation reactions suggests that this solvent system is also unrealistic. [18][19][20] Recently studies have demonstrated solvent stability during cycling in dimethylsulfoxide (DMSO), acetonitrile and N,Ndimethylacetamide (DMA) electrolytes. [21][22][23][24][25] However, these solvents are also known to be unstable in contact with lithium, therefor making the construction of real cells problematic.One of the most promising candidate electrolytes is dimethylsulfoxide (DMSO). [23][24][25][26] However, the stability of the lithium metal electrode in contact with this electrolyte has been questioned (the effect of which is negated in proof of concept cells where a large excess of Li is used). This instability is because the reduction products of DMSO and the lithium salt do not form a stable passivation layer on the metal surface. In this short letter we aim to highlight the concept of using electrolyte additives which can participate in the formation of an effective SEI layer which will act to protect the surface of the lithium metal.The e...

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Surface Characterization of the Carbon Cathode and the Lithium Anode of Li–O₂ Batteries Using LiClO₄ or LiBOB Salts

Cited by 66 publications

References 44 publications

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

XPS Study of the Interface Evolution of Carbonaceous Electrodes for Li-O₂Batteries during the 1st Cycle

Increased Cycling Efficiency of Lithium Anodes in Dimethyl Sulfoxide Electrolytes For Use in Li-O2 Batteries

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Surface Characterization of the Carbon Cathode and the Lithium Anode of Li–O2 Batteries Using LiClO4 or LiBOB Salts

Cited by 66 publications

References 44 publications

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

Binder-free nitrogen-doped carbon paper electrodes derived from polypyrrole/cellulose composite for Li–O2 batteries

XPS Study of the Interface Evolution of Carbonaceous Electrodes for Li-O2Batteries during the 1st Cycle

Increased Cycling Efficiency of Lithium Anodes in Dimethyl Sulfoxide Electrolytes For Use in Li-O2 Batteries

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Surface Characterization of the Carbon Cathode and the Lithium Anode of Li–O₂ Batteries Using LiClO₄ or LiBOB Salts

XPS Study of the Interface Evolution of Carbonaceous Electrodes for Li-O₂Batteries during the 1st Cycle