In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).

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A review of electrode materials for electrochemical supercapacitors

2.1. Solvents 4307 2.1.1. Propylene Carbonate (PC) 4308 2.1.2. Ethers 4308 2.1.3. Ethylene Carbonate (EC) 4309 2.1.4. Linear Dialkyl Carbonates 4310 2.2. Lithium Salts 4310 2.2.1. Lithium Perchlorate (LiClO4) 4311 2.2.2. Lithium Hexafluoroarsenate (LiAsF6) 4312 2.2.3. Lithium Tetrafluoroborate (LiBF4) 4312 2.2.4. Lithium Trifluoromethanesulfonate (LiTf) 4312 2.2.5. Lithium Bis(trifluoromethanesulfonyl)imide (LiIm) and Its Derivatives 4313

/pdf/nonaqueous-liquid-electrolytes-for-lithium-based-uxm5ffbi18.pdf

Nonaqueous liquid electrolytes for lithium-based rechargeable batteries.

Research Development on Sodium-Ion Batteries

Electrolytes and interphases in Li-ion batteries and beyond.

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

A new lithium salt based on a chelated borate anion, BOB [bis(oxalato)borate] is evaluated as the electrolyte solute for lithium-ion cells by both electrochemical means and cell testing. Controlled potential coulometry study reveals that the anion can stabilize aluminum substrate to more positive potentials than the popular hexafluorophosphate anion does, while slow scan cyclic voltammograms show good compatibility of the salt with graphitizable carbonaceous anode as well as satisfactory stability against charged cathode surface. The lithium-ion cells containing this salt as electrolyte solute exhibit excellent capacity utilization, capacity retention as well as rate capability at room temperature. Probably due to the fact that the new anion contains no labile fluorine and is thermally stable, electrolyte solutions based on it demonstrate stable performance in cells even at 60°C, where -based electrolytes would usually fail. The preliminary results reported herein provide a possible solution to the instability of the Li-ion cell performance at the elevated temperatures anticipated for heavy duty applications such as electric or hybrid electric vehicle missions. © 2001 The Electrochemical Society. All rights reserved.

https://iopscience.iop.org/article/10.1149/1.1426042/pdf

LiBOB as Salt for Lithium-Ion Batteries:A Possible Solution for High Temperature Operation

Using ac impedance, we studied the formation process of solid electrolyte interface (SEI) film on graphite electrode during initial cycles. Results show that the SEI formation takes place through two major stages. The first stage takes place at voltages above 0.25 V (before lithiation of graphite), during which a loose and highly resistive film is formed. The second stage occurs at a narrow voltage range of 0.25-0.04 V, which proceeds simultaneously with lithiation of graphite electrode. In the second stage, a stable, compact, and highly conductive SEI film is produced. © 2001 The Electrochemical Society. All rights reserved.

https://iopscience.iop.org/article/10.1149/1.1414946/pdf

Understanding Solid Electrolyte Interface Film Formation on Graphite Electrodes

Using alkyl phosphates and a cyclophosphazene as cosolvents, the possibility of formulating a nonflammable electrolyte for lithium-ion batteries was explored. The emphasis was placed on determining the impact of these flame-retarding additives on the performance of the electrolyte. It was found that although the cosolvents at high contents effectively suppress the flammability of the electrolyte, their flame-retarding effectiveness is still insufficient to render the electrolytes completely nonflammable. Furthermore, such reduction in electrolyte flammability is always realized at the expense of performance; electrochemical instability of phosphates results in severe capacity fading, while high viscosity of these cosolvents reduces both capacity utilization and power. © 2002 The Electrochemical Society. All rights reserved.

An Attempt to Formulate Nonflammable Lithium Ion Electrolytes with Alkyl Phosphates and Phosphazenes

Electrolyte is an indispensable component of any electrochemical cell. Among the properties of an electrolyte, its inertness toward electrochemically induced electronation (reduction at negatively charged electrode) and de-electronation (oxidation at positively charged electrode) has the most direct influence over the operation of the cell. As an ionic conductor in contact with the electrodes at different potentials, electrolyte in most cases is expected to maintain this inertness against both oxidation and reduction while the desired electrochemical process is in progress at the electrodes. The authors scrutinized the conventional practice of measuring an electrolyte stability window. It is shown that misleading values might be generated by this practice. Thus, the authors recommend that to obtain a real stability window, the working electrode material should simulate the electrodes used in a real device. Further, in applications that have a high-surface-area electrode, a new quantification of a stability window is proposed. The electrochemical stability values of various nonaqueous electrolytes that are derived this way should reflect the actual operation limits of these electrolytes in real-life devices.

Toward Reliable Values of Electrochemical Stability Limits for Electrolytes

The oxidative stability and initial oxidation-induced decomposition reactions of common electrolyte solvents for batteries and electrical double layer capacitors were investigated using quantum chemistry (QC) calculations. The investigated electrolytes consisted of linear (DMC, EMC) and cyclic carbonate (EC, PC, VC), sulfone (TMS), sulfonate, and alkyl phosphate solvents paired with BF4–, PF6–, bis(fluorosulfonyl)imide (FSI–), difluoro-(oxalato)borate (DFOB–), dicyanotriazolate (DCTA–), and B(CN)4– anions. Most QC calculations were performed using the M05-2X, LC-ωPBE density functional and compared with the G4MP2 results where feasible. The calculated oxidation potentials were compared with previous and new experimental data. The intrinsic oxidation potential of most solvent molecules was found to be higher than experimental values for electrolytes even after the solvation contribution was included in the QC calculations via a polarized continuum model. The presence of BF4–, PF6–, B(CN)4–, and FSI– anions...

T. Richard Jow

Papers

LiBOB as Salt for Lithium-Ion Batteries:A Possible Solution for High Temperature Operation

Understanding Solid Electrolyte Interface Film Formation on Graphite Electrodes

An Attempt to Formulate Nonflammable Lithium Ion Electrolytes with Alkyl Phosphates and Phosphazenes

Toward Reliable Values of Electrochemical Stability Limits for Electrolytes

Oxidative Stability and Initial Decomposition Reactions of Carbonate, Sulfone, and Alkyl Phosphate-Based Electrolytes