Prevention against Oxidation of Mn Evaporant during Reactive Evaporation Process

Noguchi

Hayakawa

et al. 2014

The LiMn2O4 thin films for Li secondary batteries have been prepared by a RF magnetron sputtering method. In this research, we have prepared LiMn2O4 films under various preparation conditions. The charge-discharge characteristics of these films were evaluated. Several films showed good charge-discharge curve and good voltage, but charge-discharge efficiency was not so good. It was shown that the capacity of a film was approximately half of the theoretical value. KeywordLiMn 2 O 4 thin film, RF magnetron sputtering, Li secondary batteries INTRODUCTIONRecently, an attention has been paid to the cars that run by using clean energy such as electric cells, fuel cells, and hybrid-power cells. They are intended to decrease the exhaust gases. However, there are a lot of problems of these cars. For example, the distance that they can run for one charge is short. It takes long time to charge the batteries. The place of charging batteries is few, etc.The Li secondary battery has a high energetic density and a high voltage that exceeds the electrolysis voltage of water. So non-water electrolyte should be used. These contribute to the miniaturization of the battery size.For a lithium secondary battery, the manganese based materials were paid attention for cathode.

“…The doughnuttype plate was put on the shutter through this work. [25,26] This plate has a hole of 30 mmφ. The potential of this plate is grounded and equal to the shutter potential.…”

Section: Introductionmentioning

confidence: 99%

Improvement of battery properties of LiMn2O4 thin films

Noguchi

Hayakawa

et al. 2014

“…These weak points would be resolved by using Li secondary batteries. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The Li secondary battery has a high energetic density and a high voltage that exceeds the electrolysis voltage of water. So non-water electrolyte should be used.…”

Section: Introductionmentioning

confidence: 99%

“…The use of LiMn 2 O 4 instead of LiCoO 2 has been proposed. [8][9][10][11][12][13][14][15][16][17][18][19][20] If LiMn 2 O 4 is used, the problems in the resource and the toxicity could be cleared, and we can make the secondary batteries with lower price than those of LiCoO 2 electrodes.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10][11][12][13][14][15][16][17][18] This is because Mn 3 O 4 has the spinel structure, this structure can accept Li ions easily, and has a longer lifetime as compared with other electrodes. [1][2][3][4][5][6][7] However, when the Mn 3 O 4 thin films were used as a positive-electrode, and the Li thin films were used as a negative-electrode, we couldn't measure the battery characteristics.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of deposition condition of LiMn2O4 films prepared by RF magnetron sputtering

Nakamura

2012

Self Cite

The LiMn 2 O 4 films for Li secondary batteries have been prepared by a RF magnetron sputtering method. This research was designed for investigating the deposition condition of the films. The parameters were sputtering time, RF power, sputtering pressure and sputtering atmosphere. The LiMn 2 O 4 films were deposited on the Al substrates, and their film properties were evaluated by X-ray diffraction. The film thickness was estimated by the gravimetry method. It was shown that the film thickness and the deposition rate were proportional to the Ar：O 2 ratio as well as the sputtering time and the RF power. It was also shown that the deposition rate decreased as increasing the sputtering pressure.Keyword LiMn 2 O 4 thin film, RF magnetron sputtering, Li secondary batteries IntroductionRecently, an attention has been paid to the cars that run by using clean energy such as electric cells, fuel cells, and hybrid-power cells. They are intended to decrease the exhaust gases. However, there are a lot of problems of these cars. For example, the distance that they can run for one charge is short, the lifetime of battery is short, and the place that can be charged is few, etc.Then, we pay attention to the battery that is the source power of the electric car. Nickel hydride batteries are chiefly installed in the electric cars. They have excellent characteristics during the discharge with high-power and large current. They are also safety material. However, they have weak points, for example, increasing self-discharge, and the memory effect, so the capacity seems to decrease. These weak points would be resolved by using Li secondary batteries.

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23] In our early studies, Mn 3 O 4 films have been successfully prepared. [15][16][17][18][19][20][21][22][23] But, unfortunately, charge-discharge curves could not be measured. It seems that this is due to the deficiency of Li ions moving between positive and negative electrodes during charge and discharge process.…”

Section: Introductionmentioning

confidence: 99%

Preparation of LiMn2O4 Films by RF Magnetron Sputtering Method

Nakamura

Hosokawa

et al. 2009

Self Cite

Lithium-manganese oxides have been studied as a cathode material in the Li secondary batteries. Preparation of LiMn 2 O 4 thin films was tried with a RF magnetron sputtering method at the substrate temperature (T sub) of R.T.. This material is superior to other materials in the cost performance as well as non-toxicity. The dependence of crystal properties on the Ar flow rate was examined. In the case of 60 min deposition time, the deposition rate was not varied as varying Ar flow rate from 2 to 3.5 sccm.