| 71. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Electrochemical properties of a full cell of lithium iron phosphate cathode using thin amorphous silicon anode
- 2014
-
Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 268:Part B, s. 256-260
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon-coated lithium iron phosphate (LiFePO4/C) with uniform carbon coating was synthesized by a mechanical activation method. Silicon negative electrode material was obtained in the form of thin films of amorphous silicon on a Cu foil substrate by vertical deposition technique. The electrochemical performance of the full cell, LiFePO4/C-Si, was tested with 1 M LiPF6 in EC/DMC at 0.5 and 1 C-rates. The cell exhibited an initial discharge capacity of 143.9 mAh g(-1) at 0.5 C-rate at room temperature. A reasonably good cycling performance under a high current density of 1 C-rate could be obtained with the full cell.
|
|
| 72. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Highly porous LiMnPO4 in combination with an ionic liquid-based polymer gel electrolyte for lithium batteries
- 2011
-
Ingår i: Electrochemistry Communications. - : Elsevier BV. - 1388-2481. ; 13:10, s. 1105-1108
-
Tidskriftsartikel (refereegranskat)abstract
- A porous well defined LiMnPO(4) cathode material is synthesized by a sol-gel method. The electrochemical performance of the cathode material is evaluated in a cell with an ionic liquid-based polymer electrolyte (0.5 M LITFSI in EMlmTFSI) and a lithium metal electrode. The results are compared to a cell with a traditional organic carbonate-based electrolyte (1 M LiPF(6) in EC/DMC). The cell with the ionic liquid-based polymer electrolyte presents an enhanced electrochemical intercalation performance of lithium ions, a high electrochemical stability window of 5 V, and an excellent cycling ability as compared with the organic based counterpart. Furthermore, the ionic liquid-based polymer gel electrolyte effectively prevents the dissolution of manganese - otherwise a common problem.
|
|
| 73. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Improving the stability of an organic battery with an ionic liquid-based plymer electrolyte
- 2012
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:26, s. 9795-9797
-
Tidskriftsartikel (refereegranskat)abstract
- A gel polymer electrolyte based on the ionic liquid {N-butyl-N-methyl-pyrrolidiniumbis(trifluoromethanesulfonyl) imide (Py14TFSI) and lithium bis(trifluoromethanesulfony)imide (LiTFSI)} is shown to prevent the dissolution from an organic electrode. The composite cell shows high energy efficiency although poor cycle stability is exhibited at very high current density (10 C-rate).
|
|
| 74. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Nano-fibrous polymer films for organic rechargeable batteries
- 2013
-
Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:7, s. 2426-2430
-
Tidskriftsartikel (refereegranskat)abstract
- We propose a nano-fibrous polymer (NFP) film, fabricated by electrospinning poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), as a key component in high performance organic batteries. The new strategy with a NFP film enables extraordinary rate capability and excellent cyclability, due to its special morphology. Moreover, the NFP film enhances the flexibility of the electrode at a low cost and prevents dissolution of PTMA into the electrolyte.
|
|
| 75. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Preparation and application of TEMPO-based di-radical organic electrode with ionic liquid-based polymer electrolyte
- 2012
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:27, s. 10394-10399
-
Tidskriftsartikel (refereegranskat)abstract
- In this study we report the synthesis and use of new organic materials, TEMPO di-radical [1,3-bis(4-(2,2,6,6,-tetramethyl-1-oxyl-4-piperidoxyl)butyl) imidazolium trifluorosulfonate]. Two cells were prepared with Li metal anode and the TEMPO di-radical based cathode with a microporous polymer electrolyte [1-butyl-3-methyl imidazolium bis(trifluoromethane sulfonyl) imide (BMImTFSI) in 0.5 M LiTFSI, and in 1 M LiPF6 in ethylene carbonate/dimethyl carbonate (EC/DMC)] hosted in electrospun poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) membrane. The nature of the solvent was not found to affect the basic redox reaction behavior of TEMPO. The anodic and cathodic peaks were obtained at almost the same position and with some difference in the separation of peaks. The presence of BMImTFSI significantly affects the electrochemical performance of the battery as the cell having this RTIL exhibited far better electrochemical performance with 100% utilization of the active material and reasonably good cycling performance up to 200 cycles. We believe that this composite cell will contribute to organic green rechargeable batteries, although the cell is not fully organic composite.
|
|
| 76. |
|
|
| 77. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
-
Towards flexible secondary lithium batteries: polypyrrole-LiFePO4 thin electrodes with polymer electrolytes
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 22:30, s. 15045-15049
-
Tidskriftsartikel (refereegranskat)abstract
- A thin flexible polypyrrole-lithium iron phosphate (PPy-LiFePO4) based cathode has been fabricated. A slurry containing carbon black, a binder and the active material prepared by direct polymerization of pyrrole on the surface of LiFePO4 (LFP) was spread on an Al/carbon film substrate by the doctor blade method. Transmission electron micrographs reveal that PPy nanoparticles form a web like structure over the surface of LFP particles. After doping with lithium ions the PPy network becomes conducting. When evaluated as a cathode of 180 mu m thickness together with a gel polymer electrolyte and a lithium anode, the charge-discharge performance reveals that the electrochemical properties of LFP are influenced to a considerable extent by the PPy. The cells show high initial discharge capacities of 135 and 110 mA h g(-1) for 0.041 (C/10) and 0.21 (C/2) mA cm(-2), respectively, and high active material utilization. Furthermore the cells exhibit stable cycle properties even at 0.21 mA cm(-2) with a low capacity fade per cycle (similar to 0.3%).
|
|
| 78. |
- Klein, Antoine, 1998, et al.
(författare)
-
Identifying the Role of Electrolyte Additives for Lithium Plating on Graphite Electrode by Operando X-ray Tomography
- 2024
-
Ingår i: Batteries and Supercaps. - 2566-6223. ; 49:12, s. 5060-5083
-
Tidskriftsartikel (refereegranskat)abstract
- The plating of lithium metal on the graphite electrode is a major degradation mechanism in lithium-ion batteries (LIBs). It brings a significant risk of internal shortcircuit by penetration of dendritic lithium through the separator, leading to short cycle life and safety issues. Understanding how and when plating occurs is crucial for the development of mitigation strategies, e. g. tuning the electrolyte composition. Here we present an operando X-ray tomographic microscopy (XTM) study to directly monitor the plating of lithium metal in a lithium/graphite cell. XTM enables a non-destructive and quantitative characterization at operando conditions of lithium deposition on a graphite electrode at relevant conditions. In this work it allows us to probe the role of the electrolyte additives vinylene carbonate (VC) and lithium bis(fluorosulfonyl)imide (LiFSI) in the standard LIB electrolyte LP57 (base electrolyte without additives). The additives show overall better performances in terms of delayed onset of lithium plating which is important for the utilisation of the full capacity of graphite intercallaiton. We show that there is a transition during lithiation of the dominating mechanism, once lithium plating is initiated this rapidly becomes dominating and hinders further intercalation. For the base electrolyte a homogeneous and dense morphology of plated lithium is found, whereas a more dendritic morphology is observed in the presence of additives. During delithiation, there is a rapid stripping of some of the plated lithium followed by deintercalation. In addition, our work provides a general methodology to track the morphology of plated lithium, which is crucial for fundamental research about battery safety.
|
|
| 79. |
- Lacarbonara, Giampaolo, et al.
(författare)
-
Operando insights into ammonium-mediated lithium metal stabilization: surface morphology modulation and enhanced SEI development
- 2024
-
Ingår i: Journal of Colloid and Interface Science. - 1095-7103 .- 0021-9797. ; 669, s. 699-711
-
Tidskriftsartikel (refereegranskat)abstract
- Lithium-ion batteries (LiBs) with graphite as an anode and lithiated transition metal oxide as a cathode are approaching their specific energy and power theoretical values. To overcome the limitations of LiBs, lithium metal anode with high specific capacity and low negative redox potential is necessary. However, practical application in rechargeable cells is hindered by uncontrolled lithium deposition manifesting, for instance, as Li dendrite growth which can cause formation of dead Li, short circuits and cell failure. The electrochemical behaviour of a protic additive (NH4PF6) in a carbonate-based electrolyte has been investigated by operando confocal Raman spectroscopy, in situ optical microscopy, and X-ray photoelectron spectroscopy, elucidating its functional mechanism. The ammonium cation promotes a chemical modification of the lithium metal anode-electrolyte interphase by producing an N-rich solid electrolyte interphase and chemically modifying the lithium surface morphology by electrochemical pitting. This novel method results in stable lithium deposition and stripping by a decreasing the local current density on the electrode, thus limiting dendritic deposition.
|
|
| 80. |
- Larsson Wexell, Cecilia, 1965, et al.
(författare)
-
Electropolished titanium implants with a mirror-like surface support osseointegration and bone remodelling
- 2016
-
Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8434 .- 1687-8442.
-
Tidskriftsartikel (refereegranskat)abstract
- This work characterises the ultrastructural composition of the interfacial tissue adjacent to electropolished, commercially pure titanium implants with and without subsequent anodisation, and it investigates whether a smooth electropolished surface can support bone formation in a manner similar to surfaces with a considerably thicker surface oxide layer. Screw-shaped implants were electropolished to remove all topographical remnants of the machining process, resulting in a thin spontaneously formed surface oxide layer and a smooth surface. Half of the implants were subsequently anodically oxidised to develop a thickened surface oxide layer and increased surface roughness. Despite substantial differences in the surface physicochemical properties, the microarchitecture and the composition of the newly formed bone were similar for both implant surfaces after 12 weeks of healing in rabbit tibia. A close spatial relationship was observed between osteocyte canaliculi and both implant surfaces. On the ultrastructural level, the merely electropolished surface showed the various stages of bone formation, for example, matrix deposition and mineralisation, entrapment of osteoblasts within the mineralised matrix, and their morphological transformation into osteocytes. The results demonstrate that titanium implants with a mirror-like surface and a thin, spontaneously formed oxide layer are able to support bone formation and remodelling.
|
|
