Characterization of advanced electrode materials by means of ion beam analysis technique for next generation Li-ion batteries

Transcription

1 Characterization of advanced electrode materials by means of ion beam analysis technique for next generation Li-ion batteries Spanish leader Prof. J. Manuel Perlado Martin Japanish leader Prof. Yoshiaki Kato

2 Outline Motivation. Ion Beam Analysis Techniques for Li characterization. Experimental results on Li distribution characterization in Li-ion batteries positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5). Experimental results on Li depth profiling in LiFeP. Conclusions.

3 Motivation

4 Motivation Li-ion batteries consist of a positive and a negative electrode separated by an electrolyte layer. When electrodes are linked by an external circuit, spontaneous electrochemical reactions, which involve Li diffusion, take place. Therefore, the performance of a Li-ion battery (energy density, power, capacity, charge and discharge rates and lifetime) strongly depends, among other factors, on the characteristic of the electrodes and in particular on the Li diffusion capabilities on them. Further development of Li-ion batteries requires Li characterization.

5 Available techniques for Li ion batteries characterization

6 Li characterization Two remaining questions: Can we measure the Li concentration? If so, can we measure it during the charge-discharge processes?

7 Li characterization The Electrochemical Society Interface Fall 2011 TEM and EELS are techniques with surface sensitivity can not be applied to real electrodes. No quantitative information

8 Charge and discharge processes Interest in the Li movement Can we measuring the batteries microstructure and composition during the charge-discharge processes? YES,.. BUT Detailed structure of the XRD pattern during the first charging process. In-situ XRD diffraction of C- LiFe 0.6 Mn 0.4 PO 4 during the first charge-discharge cycle. From XRD measurements only information about the crystalline phases can be obtained Is the Li always present in crystalline phases?

9 Ion Beam Analysis tecniques (IBA) ion source MeV-Ion-Accelerator Analysismagnet Iman conmutador RBS NRA PIGE Scattered Ions Nuclear reaction Products γ - rays Electrons Ion lens PIXE X-rays ERDA Recoil ions Target Courtesy of Dr. F. Munnik

10 IBA for Li characterization Characterize the Li distribution by means of PIGE spatial characterization NRA depth profiling Advantages: Quantitative information about the elemental distribution. Simultaneous measurement of different elements. PIXE, PIGE and NRA spectra can be simultaneously measured. The use of micro-beams allow good spatial resolution. The use of external micro-beams allow measure large samples. The use of NRA allow measuring the Li depth profiling without destroying samples.

11 IBA for Li characterization: necessity for cooperation SPAIN CMAM/UAM JAPAN TIARA/JAEA CNA/US 3/14/2013

12 Li distribution characterization in positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5) Objectives Characterize the elemental distribution in Li-ion battery positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 (1.0 x 0.5) microparticles: As received (non-charged) Charged Study the dependence of the Li distribution on: Electrode thickness. Charging conditions. For these aims, cross-sectional samples need to be fabricated

13 Li distribution characterization in positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5) As-received electrode Li-rich and Li-depleted regions μ-particles distribution. As-received individual microparticles K. Mima et al. NIMB 290 (2012) 79 The Li distribution is homogeneous within the individual μ-particles. We thank the team of TOYOTA for supplying and preparation of the samples as well as, for the very nice cooperation.

14 Li distribution characterization in positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5) One single measurements gives information about the constituents of Active material: Ni, Co, Al.. Binder: F, O,.. Li yield is higher for the uncharged than for the charged electrode. The Ni yield is the same in both electrode. K. Mima et al. NIMB 290 (2012) 79 Li/Ni AR ~1.10 Li/Ni Ch ~0.94

15 Li distribution characterization in positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5) Thickness dependence: Th= 105 μm Th (μm) d c (ma/c m 2 ) t (min) Th= 35 μm K. Mima et al. NIMB 290 (2012) 79 The Li distribution is more homogeneous for the thin than for the thick electrode.

16 Li distribution characterization in positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 secondary particles (1.0 x 0.5) Charge rate dependence: 6m A/cm 2 15 min. 0.6 ma/cm min. Li inhomogeneously distributes in both electrodes Fast charge Homogeneous gradient in the Li distribution Slow charge Two regions with an abrupt boundary between them. K. Mima et al. NIMB 290 (2012) 79

17 CONCLUSIONS μ-pige and μ-pixe techniques are successfully applied to accurately measure the elemental (in particular Li) distribution in Li-ion batteries. Li inhomogenously distributes in the electrode the secondary particles. to the random distribution of The Li distribution within as-received individual secondary particles turns out to be homogeneous. The Li distribution in the cross sections of the electrodes is observed to depend on electrode thickness and on charge conditions. The Li distribution is: Homogeneous in a thin electrode (35 μm), Inhomogeneous when increasing the thickness (105 μm). For the thick electrode (105μm) slow charge rate gives rise to a small gradient of the Li distribution in the electrode regions close to the Al current collector.

18 CONCLUSIONS Answer to questions: Can we measure the Li concentration? Yes, we can. Can we measure it during the charge-discharge processes? For the time being we have demonstrated that it can be measured in charged and uncharged batteries.

19 Manpower Prof. José Manuel Perlado Prof. Emilio Minguez Dr. Jesús Álvarez Assoc. Prof. Emma del Río Assoc. Prof. Raquel Gonzalez Arrabal Assoc. Prof. Antonio Rivera Miguel Panizo Prof. Yoshiaki Kato (GPI) Prof. Kunioki Mima (GPI) Prof. Sadao Nakai (GPI) Assoc. Prof. Kazuhisa Fujita (GPI) Prof. Yoshiharu Uchimoto (Kyoto University) Dr. Hirozumi Azuma (TCRL) Dr. Yoshio Ukyo (TCRL) Prof. Hiroaki Nishimura (ILE) Prof. Tomihiro Kamiya (TIARA)