Mechanochemical synthesis and investigation of nanomaterials for lithium-ion. ion batteries. N.V. Kosova. MolE 2012 Dubna, August 27-30

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1 Mechanochemical synthesis and investigation of nanomaterials for lithium-ion ion batteries N.V. Kosova Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia MolE 2012 Dubna, August 27-30

2 Outline Intercalation electrode materials for lithium-ion batteries. Challenge for nanosized materials Mechanical activation as a promising method to prepare nanomaterials. Synthetic reactions Investigation of as prepared materials. Some examples Composite cathode materials 2

3 Structural types of cathode materials Spinel (3D) Layered (2D) Frame-work (1D) LiО 2 СоО 2 LiО 2 c CoО 2 LiО 2 CoО 2 LiО 2 Fe Li P a 3

4 Comparison of cathode materials Compound/ property Electric conductivity Structural, chemical and thermal stability Complexity of synthesis LiCoO 2 LiMn 2 O 4 decreases increases increases LiFePO 4 4

5 Materials prepared via mechanochemical route Layered structured LiCoO 2 LiCo 1-x M x O 2 LiCoO 2 -Li 2 MnO 3 LiNiO 2 LiNi 1-x Co x O 2 LiNi 1-x-y Co x Mn y O 2 LiV 3 O 8 Spinel structured LiMn 2 O 4 LiMn 2-x M x O 4 LiMn 1.5 Ni 0.5 O 4 (5V) Li 4 Ti 5 O 12 (anode) Frame-work structured LiFePO 4 LiFe 1-x Mn x PO 4 LiMnPO 4 LiCoPO 4 LiNiPO 4 Li 2 CoPO 4 F Li 2 NiPO 4 F LiVPO 4 F Li 2 FeP 2 O 7 LiTi 2 (PO 4 ) 3 (electrolyte) 5

6 Pros and cons of nanosized electrode materials The particle size (and its distribution), morphology and density of the particles play a fundamental role on electrochemical performance of electrode materials Shorter Li + diffusion paths; increased electrode/ electrolyte surface contact; accelerated ionic transport Better utilization of nanoparticle volume Smaller dimensional changes upon cycling; better adaptability of nanoparticles to volume changes under cycling Enhanced high-rate capability Increased practical capacity Improved structural stability Intensification of undesirable electrode/electrolyte reactions due to high surface area (self-discharge, poor cycling and calendar life) Inferior packing of particles (low volumetric energy densities) Potentially more complex synthesis 6

7 Mechanical activation method Synthetic reactions 7

Nanomaterials via mechanical activation MA Т, С Two-step process: 1 step (MA) grinding and

2 step (T) short-time thermal treatment formation of product from molecular precursor

intermediate stages Acceleration and simplification of the synthetic process Increase in

8 Nanomaterials via mechanical activation MA Т, С Two-step process: 1 step (MA) grinding and plastic deformation of solids mixing of components at molecular level (deformation mixing); 2 step (T) short-time thermal treatment formation of product from molecular precursor supersaturated by defects Laboratory planetary mill AGO-2 Decrease in a number of intermediate stages Acceleration and simplification of the synthetic process Increase in homogeneity of the final product Formation of nano-sized / nano-structured material Industrial activator CEM-7 8

9 Synthetic reactions Soft mechanochemical synthesis (SMS) Mechanochemically assisted carbothermal reduction of d-metal compounds (CTR) Mechanochemically assisted interaction of covalent compounds with ionic salts Motivation - to realize fast propagating synthesis in order to reduce contamination and energy consumption and to prepare nanosized products. 9

10 1. Soft mechanochemical synthesis (SMS) SMS is generally based on the acid-base properties of the reagents. MA T А(ОН) х + В(ОН) y AB(OH) m nh 2 O ABO z 1. Acceleration of initial interaction due to participation of OH groups in the processes of proton and electron transfer. 2. Formation of chemically active X-ray amorphous precursor. 3. Formation of final product by heating the precursor at moderate temperatures. 4. Significant reduction of contamination due to lower hardness of initial reagents. 5. Preparation of nanosized, pure and homogeneous final product as a result. 10

11 SMS: LiMn 2 O 4 LiOH + MnO x LiMn 2 O 4 MnO Mn 2 O 3 MnO 2 acidity increases (a) - MnO - Mn 2 O 3 - Li-Mn spinel 111 (b) MnO Mn 2 O o C 600 o C MnO o C MA , degree , degree X-Ray patterns of (a) mechanically activated mixtures of LiOH with different Mn oxides and (b) the products of MA and annealing at different temperatures. SMS - fast propagating mechanochemical reaction (realized at the stage of MA) N.V. Kosova et al., Solid State Ionics 135 (2000) N.V. Kosova et al., J. Power Sources (2001)

12 SMS: LiV 3 O 8 2LiOH + 3V 2 O 5 2LiV 3 O 8 + H 2 O (a) Absorbance as (V-O) s (V-O) (V=O) (b) V 2 O , degree Wavenumber, cm -1 X-ray patterns (a) and FTIR spectra (b) of the LiOH+V 2 O 5 mixtures activated for (1) 30 sec, (2) 1 min, (3) 5 min, (4) 10 min, (5) 10 min followed by annealing at 400C, (6) 5 min followed by aging for 6 months. V 2 O 5 ; LiV 3 O 8 ; Li-V bronzes N.V. Kosova et al., J. Solid State Chem. 160 (2001)

Carbothermal reduction method is relied on the use of carbon both as a selective reducing and covering agent

13 2. Carbothermal reduction The potential low-cost advantage of LiFePO 4 is not realized if expensive Fe 2+ precursors are used as reagents. Carbothermal reduction method is relied on the use of carbon both as a selective reducing and covering agent (J. Barker, 2003) : 1) Fe 3+ compounds are cheaper than Fe 2+ salts; 2) less hazardous gases are formed during firing; 3) more easy to scale-up. Cryst. С C LiFePO 4 Amorph. C LiFePO 4 13

14 Mechanochemically assisted CTR of Fe 2 O 3 Li 2 CO 3 + Fe 2 O 3 + C + 2(NH 4 ) 2 HPO 4 2LiFePO 4 + 3H 2 O + 4NH 3 +CO 2 + CO - LiFePO 4 [19-721] - Fe 2 O 3 [33-664] - Fe 3 O 4 [19-629]? - (NH 4 ) 2 HPO 4 [29-111] monocl. - (NH 4 ) 2 HPO 4 [20-84] orhtorh. - LiFeP 2 O 7 [ ] - Li 3 Fe 2 (PO 4 ) 3 [47-107] - NH 4 FeP 2 O 7 {21-26] - Li 3 PO 4 [ ] , , , 221, o C 550 o C 450 o C 300 o C MA Fe 2 O 3 MA mixture MA mixture o C MA mixture o C Velocity, mm/s experiment fit Fe 2 O 3 experiment fit Fe 2 O 3 experiment fit Fe 2 O 3 Fe 3+ experiment fit Fe 2+ (LiFePO 4 ) , degree X-Ray patterns and Mössbauer spectra of the activated and annealed mixtures with Fe 2 O 3. N.V. Kosova et al., J. Electrochem. Soc. 157 (2010) A1247-A

15 Carbothermal reduction: LiMPO 4 (M=Mn Mn,, Fe, Co) Li 2 CO 3 + 2MnO 2 + 2C + 2(NH 4 ) 2 HPO 4 2LiMnPO 4 + 3H 2 O + 4NH 3 +CO 2 + 2CO Li 2 CO 3 + Fe 2 O 3 + C + 2(NH 4 ) 2 HPO 4 2LiFePO 4 + 3H 2 O + 4NH 3 +CO 2 + CO 3Li 2 CO 3 + 2Co 3 O 4 + C + 6(NH 4 ) 2 HPO 4 6LiCoPO H 2 O + 12NH 3 +3CO 2 + CO Li 2 CO 3 + 2NiO + 2(NH 4 ) 2 HPO 4 2LiNiPO 4 + 3H 2 O + 4NH 3 + CO 2 LiNiPO 4 LiCoPO 4 LiFePO 4 LiMnPO , degree 15

coordination geometry and polyhedron connectivity of the parent structure (Li 2 CoPO 4 F and Li 2 NiPO 4 F).

16 3. Covalent + ionic salts This approach, called dimensional reduction, was first outlined by Long et al. It involves a deconstruction of the bonding within a covalent metal anion framework by reaction with an ionic reagent, to provide a less tightly connected framework that retains the metal coordination geometry and polyhedron connectivity of the parent structure (Li 2 CoPO 4 F and Li 2 NiPO 4 F). On the other hand, the formation of LiVPO 4 F by incorporating of LiF into the framework of VPO 4 (S.g. Cmcm) represents a decrease in crystal symmetry, but here, a three-dimentional framework is maintained. LiCoPO 4 + LiF Li 2 CoPO 4 F LiNiPO 4 + LiF Li 2 NiPO 4 F VPO 4 + LiF LiVPO 4 F LiCoPO 4 (corner-shared CO 6 ) Li 2 CoPO 4 F (edge-shared CoO 4 F 2 ) J.R. Long, L.S. McCarty, R.H. Holm, J. Am. Chem. Soc. 118 (1996)

17 Covalent + ionic salts LiCoPO 4 + LiF Li 2 CoPO 4 F Li 2 CoPO 4 F [Khasanova et al., 2011] LiCoPO 4 Li 3 PO 4 CoO? Co? 28C_He 300C D8 Advance Bruker diffractometer, HTK 1200N temperaturecontrolled X- ray chamber , degree 400C 500C 600C 650C 700C 650C 600C 500C 400C 300C 29C_He Phase transformation under heating and cooling of the activated mixture. Fast propagating mechanochemical reaction (realized at the stage of MA) N.V. Kosova et al., Solid State Ionics doi: /j.ssi

18 Investigation of as prepared materials 18

19 Particle size and morphology Investigation methods Crystal and local structure Electronic structure Electrochemical properties X-ray powder diffraction (XRD) Thermal analysis (DTA and TG) Infrared spectroscopy (FTIR) Raman spectroscopy (RS) Mössbauer spectroscopy Nuclear magnetic resonance spectroscopy (NMR) Electron paramagnetic resonance spectroscopy (EPR) X-ray photoelectron spectroscopy (XPS) Scanning electron microscopy (SEM) Transmission electron microscopy (TEM) Galvanostatic cycling Impedance spectroscopy In situ synchrotron diffraction 19

20 Li - Mn spinels MnO C cubic T tetragonal LiMn 3 O 4 Mn 3 O 4 -Mn 2 O 3 LiMn 2 O 4 Li 1- Mn 2 O 4-4/3 Li 2 MnO 3 LiMn 2 O 4- LiMnO 2 M. Thackerey et al., 1992 Т C 3V Li 4 Mn 5 O 12 Li 6.5 Mn 5 O 12 C 4V Li 2 Mn 4 O 9 Li 1.05 Mn 1.95 O 4 Li 1+ Mn 2- O 4 -MnO 2 Li Li 4 Mn 4 Mn 5 O Mn Mn 3 O stoichiometric stoichiometricspinels spinels Li Li 4 Mn 4 Mn 5 O MnO -MnO 2 2 defect defect spinels spinels LiMn LiMn 2 O 2 4 Li 4 Li 2 Mn 2 Mn 4 O oxygen oxygen non-stoichiometric non-stoichiometricspinels spinels 20

21 Cycling of micronsized LiMn Mn 4+ O 4 5 Fd-3m Fd-3m I41/amd Jan-Teller distortion λ-mno 2 LiMn 2 O 4 Li 2 Mn 2 O 4 e g U, Volts 4 3 Single-phase reaction Two-phase reaction + e + e Mn 4+ - e [Mn 4+,Mn 3+ ] - e Mn 3+ t 2g Mn 3+ (d 4 ) x in Li x Mn 2 O 4 V/V = 10-16% 21

22 Cycling of nanosized LiMn 2 O 4 Voltage, V C 600C 800C x Li Specific capacity, mah/g dq/de C 600C 800C Charge-discharge curves of LiMn 2 O 4 -MA, annealed at different temperatures, and differential capacity plots Voltage, V Nano-spinel cannot accommodate domain boundaries between Li-rich and Li-poor phases due to interface energy, and therefore lithiation proceeds via solid solutions without domain boundaries, enabling fast Li-ion insertion. N.V. Kosova, E.T. Devyatkina, Russ. J. of Electrochem. 48 (2012)

23 LiNi Mn O 4 : structure and properties Voltage, V C P V cathode material: Ni 2+ two-electron reaction Mn 4+ electrochemically non-reactive Specific capacity, ma*h*g C 5,0 Voltage, V 4,5 4,0 3, Specific capacity, ma*h*g -1 Fd3m N.V. Kosova et al., 16 IMLB, Jeju, Korea, June 17-22,

24 Synthesis of layered LiNi Co 0.2 O 2 From double hydroxides From anhydrous oxides 1 m 1 m LiOH + (Ni 0.8 Co 0.2 )(OH) 2 LiOH + NiO + Co 3 O 4 N.V. Kosova et al., Chemistry for Sustainable Development 17 (2009)

25 LiNi 1-y Co y O 2 : local structure and electrochemistry 4,25 Voltage, V 4,00 3,75 3,50 3,25 3,00 2,75 C/20 C/10 1 charge 1 discharge Specific capacity, mah/g м.д. C/ Li MAS NMR spectra of LiNi 1-y Co y O 2 : 50 y = 1 (1); y = 0.8 (2); y = 0.6 (3); y = (4); y = 0.2 (5); y = 0 (6). Specific capacity, mahg C/5 C/2 C Cycle number y = 0,2; 0,4; 0,6; 0,8 25

Specific capacity, mah/g 50 100 150 200 Specific capacity, mah/g Increased ranges of solid solution

26 LiFePO 4 : effect of nano-sizing and surface disordering Prepared from FeC 2 O 4 450C 700C 200 nm 200 nm 200 nm 4, C 4, C Voltage, V 3,5 3,0 Voltage, V 3,5 3,0 2,5 2, Specific capacity, mah/g Specific capacity, mah/g Increased ranges of solid solution formation, decreased miscibility gap N.V. Kosova et al., J. Electrochem. Soc. 157 (2010) A1247-A

27 Mechanism of Li deintercalation in nano-sized LiFePO 4 Nano-particles Micro-particles Full capacity at high rates Capacity is partially lost Two-phase mechanism limits phase boundary movement because of low mutual solubility and slow migration of charge carriers. Solid solutions ranges σ and 1-β increase with reduction of particle size. A. Yamada et al.,

28 LiFePO 4 : effect of nano-sizing and surface disordering XRD Mössbauer spectroscopy 700C 111, , nm Velocity, mm/s ,221, , ,402, , ,113,620 a= b=6.006 c=4.693 V= C experiment fit Fe 2+ (octa) - 74% Fe 3+ (octa) - 26% 600C 450C a= b=6.005 c=4.695 V= a= b=6.002 c=4.696 V= , degree 600C 700C experiment fit Fe 2+ (octa) - 86% Fe 3+ (octa) - 14% experiment fit Fe 2+ (octa) - 92% Fe 3+ (octa) - 8% N.V. Kosova et al., 16 IMLB, Jeju, Korea, June 17-22,

29 LiFe 1-y Mn y PO 4 solid solutions Cell parameters/nm a, Å b, Å c, Å PDF Li NMR y = 1.0 y = 0.75 y = 0.5 y = 0.25 y = 0, y = ppm y in LiFe 1-y Mn y PO P NMR Chemical shift 7 Li/ppm Li data of Wilcke our data 31 P data of Wilcke our data 0,0 0,2 0,4 0,6 0,8 1, Chemical shift 31 Px10 3 /ppm y = 1 y = 0.75 y = 0.5 y = 0.25 y = 0.1 y = ppm y in LiFe 1-y Mn y PO 4 N.V. Kosova et al., Electrochim. Acta 59 (2012)

30 LiFe 1-y Mn y PO 4 : electrochemistry Potential vs. (Li/Li + )/V y = 0 y = 0.1 y = 0.25 y = 0.5 y = 0.75 y = Discharge capacity/mah g -1 Discharge capacity/mah g theor. (total) exper y in LiFe 1-y Mn y PO 4 theor. Fe 3+ /Fe 2+ exper Specific capacity/mah g Discharge capacity/mah g y in LiFe 1-y Mn y PO 4 theor. Mn 3+ /Mn 2+ exper y in LiFe 1-y Mn y PO 4 30

31 In situ synchrotron diffraction study of LiFe Mn 0.5 PO PO 4 0,143 0,38 0,588 charge 0, degree ( 0,999 N.V. Kosova et al., Solid State Ionics doi: /j.ssi

32 In situ synchrotron diffraction study of LiFe Mn 0.5 PO PO 4 Change of the (200) reflection Charge-discharge curves Change of the (200) reflection charge , ( = Å) Cell parameter, Å x=0.14 x=0.21 x=0.27 x=0.32 x=0.38 x=0.44 x=0.49 x=0.60 x=0.66 x=0.72 x=0.77 x=0.83 x=0.88 x=0.94 x=1.0 Voltage, V charge phase 1 - phase a b c Mn 2+ Mn 3+ Fe 2+ Fe Specific capacity, mah/g Cell parameters upon charge and discharge Cell parameter, Å discharge discharge , ( = Å) a - phase 1 - phase 2 b c x=0.14 x=0.17 x=0.26 x=0.32 x=0.37 x=0.43 x=0.49 x=0.54 x=0.60 x=0.66 x=0.71 x=0.77 x=0.83 x=0.88 x=0.93 x in Li x Fe 0.5 Mn 0.5 PO 4 x in Li x Fe 0.5 Mn 0.5 PO 4 Wide intermediate range of single-phase reaction was revealed. 32

c 10 μm 10 μm Without MA b d With MA 1 μm 1

instead of cubic form for ceramic samples; 3)

33 Li 1.3 Al 0.3 Ti 1.7 (PO (PO 4 ) 3 (Nasicon) solid electrolyte a c 10 μm 10 μm Without MA b d With MA 1 μm 1 μm MA samples are characterized by: 1) lower particle size and larger particle size distribution; 2) rounded form of particles instead of cubic form for ceramic samples; 3) higher Li surface concentration. N.V. Kosova et al., Ionics 14 (2008)

34 Ionic conductivity of LTP and LATP LTP log (T [SK/cm]) experiment: high-frequency low-frequency E b =0.2 ev -5 fit: bulk -6 grain boundaries total -7 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 log (T [SK/cm]) experiment: high-frequency low-frequency fit: bulk grain boundaries total E b =0.27 ev -5 1,5 2,0 2,5 3,0 3,5 4,0 4,5 LTP-MA σ = Scm -1 at room T 1000/T [K -1 ] 1000/T [K -1 ] 1 0 E b =0.23 ev E b =0.22 ev LATP log (T [SK/cm]) -2 experiment: -3 high-frequency low-frequency -4 fit: bulk -5 grain boundaries total -6 1,5 2,0 2,5 3,0 3,5 4,0 4,5 log (T [SK/cm]) experiment: high-frequency low-frequency fit: bulk grain boundaries total 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 LATP-MA σ = Scm -1 at room T 1000/T [K -1 ] 1000/T [K -1 ] MA leads to a significant increase (by a factor of a thousand) in grain boundary conductivity of LTP and LATP. 34

35 Nano-micro core-shell materials 35

MO x capsulation (non-conductive coating) Nano-micro core-shell materials LiMn 2 O 4 modification (diffusion into the core ) cryst. С composites (conductive coating) LiCoO 2 LiFePO 4 LiMeO 2 amorph.

36 MO x capsulation (non-conductive coating) Nano-micro core-shell materials LiMn 2 O 4 modification (diffusion into the core ) cryst. С composites (conductive coating) LiCoO 2 LiFePO 4 LiMeO 2 amorph. С LiCoO 2 /MO x Suppression of side reactions with electrolyte, improved stability to overcharge LiMn 2 O 4 /LiMeO 2 Suppression of Mn dissolution in electrolyte, acceleration of electron- Li-ion transport LiFePO 4 /C Increased electronic conductivity 36

Surface modification of LiCoO 2 (Al 2 O 3 ) MO x

electrolyte - improves stability to overcharge 10 m

37 Surface modification of LiCoO 2 (Al 2 O 3 ) MO x LiCoO 2 - non-conductive coating - of small thickness (<50 nm) - porous (permeable for electron and Li-ion transport) - prevents side reactions with electrolyte - improves stability to overcharge 10 m 1 m N. Kosova et al., Solid State Ionics 179 (2008)

38 Solution and MA surface modification approaches Sol 10 m 1 m MA 10 m 1 m 38

39 Electrochemical performance of LiCoO 2 /MO x LiCoO 2 /Al 2 O 3 (80 o C) Specific capacity, mah/g LiCoO 2, initial + Al 2 O 3 + TiO 2 + B 2 O 3 + MgO ppm 27 Al MAS NMR of LiCoO 2 /Al 2 O 3 LiCoO 2 /Al 2 O 3 (400 o C) LiCoO 2 /Al 2 O 3 (800 o C) Cycle number Increased discharge capacity due to a higher cut-off voltage (4.5 V) and improved cyclability N.V. Kosova et al., J. Power Sources 174 (2007)

40 LiMn 2 O 4 /LiMO 2 (M: Co, Ni, Ni Co 0.2 ) LiMn 2 O 4 LiMeO nm - conductive coating - reactive coating - suppresses Mn dissolution in electrolyte - accelerates electron/ion transport at SEI Initial LiMn 2 O nm 200 nm Solution method MA 40

41 LiMn 2 O 4 /LiMeO 2 : cycling Specific discharge capacity, mah/g ma 0.44 ma 1.1 ma LiMn 2 O 4 initial + LiCoO 2 + LiNi 0.8 Co 0.2 O ma 4.4 ma Cycle number Improvement of high-rate performance defect spinel * substituted spinel * * ppm 6 Li MAS NMR of LiMn 2 O 4, surface modified by LiCoO 2 : 1 bare, 2 annealed at 400C, 3 600C, 4 750C. N.V. Kosova et al., Solid State Ionics 192 (2011)

42 XPS study of LiMn 2 O 4 /LiMO 2 Core/shell Atomic ratio [Co]/[Mn] Atomic ratio [Ni]/[Mn] XPS Mn2p 3/2 Intensity [arb. un.] 2 1 Mn 3+ Mn 4+ LiMn 2 O 4 /LiCoO /0.049* - LiMn 2 O 4 /LiNi 0.8 Co 0.2 O /0.021* 0.016/0.024* * after Ar etching Shell practically disappears after heat treatment of ground samples at 800C due to the interaction with the core. In the case of LiNi 0.8 Co 0.2 O 2 coating, the surface concentration of Ni is lower than that of Co, probably due to accelerated diffusion of Ni ions into the bulk Binding Energy [ev] The surface concentration of Mn 3+ decreases. Mn2p 3/2 XPS spectra of pristine LiMn 2 O 4 (1) and LiMn 2 O 4 /LiCoO 2 (2). 42

43 Composite (nanodomain)) materials 43

44 Composites xlimn 2 O 4 /(1-x)LiCoO 2 (nanodomains) 1 μm 1 μm LiMn 2 O 4 LiCoO 2 1 μm MA in high-energy planetary mill followed by heat treatment at C 44

45 Composites xlimn 2 O 4 /(1-x)LiCoO 2 : cycling dq/du LiCoO 2 1st cycle 2nd cycle 10th cycle Voltage, V dq/du 2000 LiMn 2 O st cycle 2nd cycle 10th cycle Voltage, V N.V. Kosova et al., Russ. J. of Electrochemistry 45 (2009)

46 Composites xlimn 2 O 4 /(1-x)LiCoO 2 : cycling LiMn 2 O 4 /0.5LiCoO st cycle 2nd cycle 10th cycle dq/du Voltage, V The redox peaks of LiCoO 2 gradually vanished during cycling indicating the occurrence of chemical interaction. The composites are characterized by good capacity retention (100 mah/g). 46

47 Synthesis of the LiFePO 4 /Li 3 V 2 (PO 4 ) 3 composites Method A: (one-step) mechanochemically assisted combined CTR synthesis: Li 2 CO 3 + Fe 2 O 3 + V 2 O 5 + C + (NH 4 ) 2 HPO 4 xlifepo 4 / (1-x)Li 3 V 2 (PO 4 ) 3 Method B: (two-step) mechanochemically assisted mixing of two individual components: xlifepo 4 + (1-x)Li 3 V 2 (PO 4 ) 3 xlifepo 4 / (1-x)Li 3 V 2 (PO 4 ) 3 N.V. Kosova et al., 63 rd Annual Meetinf of ISE, Prague, August 19-24,

48 LiFePO 4 /Li 3 V 2 (PO 4 ) 3 : cycling LFP Voltage, V LVP 0.96LFP / 0.04LVP 0.5LFP / 0.5LVP Specific capacity, ma*h/g dq/de Voltage, V Some distinct plateaus are observed on the charge-discharge curves corresponding to two redox pairs: Fe 3+ /Fe 2+ (at 3.4 V) and V 3+ /V 4+ (above 3.4 V). Low degree of polarization in the cycling curves shows that the electron and ion transport is facile. 48 As-prepared nanocomposites show excellent stability on cycling.

49 Conclusions Mechanical activation using high-energy planetary mills is a promising solid-state method to prepare nanostructured electrode materials for Li-ion batteries Mechanical activation allows one to synthesize new composite ( core-shell, nano-domain ) materials As prepared nanostructured materials differ from bulk materials by morphology, surface/bulk composition and electrochemical properties In situ synchrotron diffraction studies evidence the differences in the mechanism of lithium insertion/deinsertion upon cycling of nanostructured and bulk electrode materials 49

50 Acknowledgements E.T. Devyatkina - XRD, cycling V.V. Kaichev - XPS A.T. Titov - SEM A.K. Gutakovsky - TEM A.B. Slobodyuk - NMR A.P. Stepanov, A.L. Buzlukov - NMR relaxation D.G. Kellermen - magnetic measurements S.A. Petrov - Mössbauer spectroscopy A.S. Ulikhin - impedance spectroscopy V.V. Ehler, A.V. Markov, V.K. Makukha - engineering 50

51 Thank you for your attention! 51

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