Kinetically Controlled Lithium-Staging in Delithiated LiFePO4 Driven by the Fe Center Mediated Interlayer Li–Li Interactions

Employing density functional theory (DFT) calculations, we demonstrate that the stage-II configuration in delithiated LiFePO4 is a thermodynamically metastable but kinetically controlled state, distinct from the thermodynamically favorable stages in graphite intercalation compounds (GICs). Based on the computational results, we propose a dual-interface model to describe the delithiation mechanism of LiFePO4 upon charging. Accordingly, the experimentally observed LiFePO4/stage-II/FePO4 three-phase coexistence could be successfully reproduced. Formation of lithium-staging configuration is mainly attributed to the Fe center mediated interlayer Li-Li interactions, which is an essential indirect electrostatic force. The indirect interaction originates from the localized nature of Fe 3d electrons, for which the effective oxidation state of Fe redox is determined by the Li ion arrangement and, in turn, has an impact on the behavior of Li ion diffusion. Besides a better understanding of the microscopic lithium diffusion mechanism in LiFePO4, our results also shed light on the interactions between electron and ion and further emphasize the importance of studying the Li diffusion kinetics at phase boundary in phase separation materials.

[1]  Rahul Malik,et al.  Kinetics of non-equilibrium lithium incorporation in LiFePO4. , 2011, Nature materials.

[2]  Byoungwoo Kang,et al.  Battery materials for ultrafast charging and discharging , 2009, Nature.

[3]  Yuki Yamada,et al.  Kinetics of Nucleation and Growth in Two-Phase Electrochemical Reaction of LixFePO4 , 2012 .

[4]  Craig A. J. Fisher,et al.  Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): Insights into Defect Association, Transport Mechanisms, and Doping Behavior , 2008 .

[5]  Takashi Ida,et al.  Isolation of Solid Solution Phases in Size‐Controlled LixFePO4 at Room Temperature , 2009 .

[6]  J. Bai,et al.  In Situ Hydrothermal Synthesis of LiFePO4 Studied by Synchrotron , 2011 .

[7]  Chunsheng Wang,et al.  Galvanostatic Intermittent Titration Technique for Phase-Transformation Electrodes , 2010 .

[8]  Yong‐Sheng Hu,et al.  Phase transformation and lithiation effect on electronic structure of Li(x)FePO4: an in-depth study by soft X-ray and simulations. , 2012, Journal of the American Chemical Society.

[9]  Anton Van der Ven,et al.  Nondilute diffusion from first principles: Li diffusion in Li x TiS 2 , 2008 .

[10]  John O. Thomas,et al.  The source of first-cycle capacity loss in LiFePO4 , 2001 .

[11]  Krishna Garikipati,et al.  The Role of Coherency Strains on Phase Stability in LixFePO4: Needle Crystallites Minimize Coherency Strain and Overpotential , 2009 .

[12]  J. L. Dodd,et al.  Phase Diagram of Li x FePO4 , 2006 .

[13]  K. S. Nanjundaswamy,et al.  Phospho‐olivines as Positive‐Electrode Materials for Rechargeable Lithium Batteries , 1997 .

[14]  Hsiao-Ying Shadow Huang,et al.  Strain Accommodation during Phase Transformations in Olivine‐Based Cathodes as a Materials Selection Criterion for High‐Power Rechargeable Batteries , 2007 .

[15]  Damian Burch,et al.  Size-dependent spinodal and miscibility gaps for intercalation in nanoparticles. , 2009, Nano letters.

[16]  T. E. Thompson,et al.  Graphite Intercalation Compounds , 1978 .

[17]  Shyue Ping Ong,et al.  Hybrid density functional calculations of redox potentials and formation energies of transition metal compounds , 2010 .

[18]  Charles Delacourt,et al.  Study of the LiFePO4/FePO4 Two-Phase System by High-Resolution Electron Energy Loss Spectroscopy , 2006 .

[19]  Martin Z. Bazant,et al.  Intercalation dynamics in rechargeable battery materials : General theory and phase-transformation waves in LiFePO4 , 2008 .

[20]  C. Delmas,et al.  Lithium deintercalation in LiFePO4 nanoparticles via a domino-cascade model. , 2008, Nature materials.

[21]  Gerbrand Ceder,et al.  Ab initio study of the migration of small polarons in olivine Li x FePO 4 and their association with lithium ions and vacancies , 2006 .

[22]  W. Craig Carter,et al.  Size-Dependent Lithium Miscibility Gap in Nanoscale Li1 − x FePO4 , 2007 .

[23]  Lin Gu,et al.  Direct observation of lithium staging in partially delithiated LiFePO4 at atomic resolution. , 2011, Journal of the American Chemical Society.

[24]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[25]  Liquan Chen,et al.  First-principles study of Li ion diffusion in LiFePO4 , 2004 .

[26]  Marnix Wagemaker,et al.  Dynamic solubility limits in nanosized olivine LiFePO4. , 2011, Journal of the American Chemical Society.

[27]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[28]  J. Bhattacharya,et al.  Understanding Li diffusion in Li-intercalation compounds. , 2013, Accounts of Chemical Research.

[29]  Tsutomu Ohzuku,et al.  Formation of Lithium‐Graphite Intercalation Compounds in Nonaqueous Electrolytes and Their Application as a Negative Electrode for a Lithium Ion (Shuttlecock) Cell , 1993 .

[30]  Karim Zaghib,et al.  Electronic, Optical, and Magnetic Properties of LiFePO 4 : Small Magnetic Polaron Effects , 2007 .

[31]  C. Ouyang,et al.  Lithium ion diffusion in Li4+xTi5O12: From ab initio studies , 2011 .

[32]  Chunsheng Wang,et al.  Strain accommodation and potential hysteresis of LiFePO4 cathodes during lithium ion insertion/extraction , 2011 .

[33]  Gerbrand Ceder,et al.  The electronic structure and band gap of LiFePO4 and LiMnPO4 , 2004, cond-mat/0506125.

[34]  M. Islam,et al.  Anti-Site Defects and Ion Migration in the LiFe0.5Mn0.5PO4 Mixed-Metal Cathode Material† , 2010 .

[35]  Linda F. Nazar,et al.  Positive Electrode Materials for Li-Ion and Li-Batteries† , 2010 .

[36]  Lin Gu,et al.  Highly ordered staging structural interface between LiFePO4 and FePO4. , 2012, Physical chemistry chemical physics : PCCP.

[37]  Lin Gu,et al.  Lithium Storage in Li4Ti5O12 Spinel: The Full Static Picture from Electron Microscopy , 2012, Advanced materials.

[38]  Montse Casas-Cabanas,et al.  Room-temperature single-phase Li insertion/extraction in nanoscale Li(x)FePO4. , 2008, Nature materials.

[39]  M. Armand,et al.  Building better batteries , 2008, Nature.

[40]  Matteo Cococcioni,et al.  Towards more accurate First Principles prediction of redox potentials in transition-metal compounds with LDA+U , 2004, cond-mat/0406382.

[41]  Daniel A. Cogswell,et al.  Suppression of phase separation in LiFePO₄ nanoparticles during battery discharge. , 2011, Nano letters.

[42]  Gerbrand Ceder,et al.  First-principles theory of ionic diffusion with nondilute carriers , 2001 .

[43]  Linda F Nazar,et al.  Proof of intercrystallite ionic transport in LiMPO(4) electrodes (M = Fe, Mn). , 2009, Journal of the American Chemical Society.

[44]  Wolfgang Dreyer,et al.  The thermodynamic origin of hysteresis in insertion batteries. , 2010, Nature materials.

[45]  B. Xu,et al.  Factors affecting Li mobility in spinel LiMn2O4—A first-principles study by GGA and GGA+U methods , 2010 .

[46]  Daniel A. Cogswell,et al.  Coherency strain and the kinetics of phase separation in LiFePO4 nanoparticles. , 2011, ACS nano.

[47]  Tomoyuki Hamada,et al.  Formation and diffusion of vacancy-polaron complex in olivine-type LiMnPO 4 and LiFePO 4 , 2011 .

[48]  J. Zaanen,et al.  Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators. , 1995, Physical review. B, Condensed matter.

[49]  Dane Morgan,et al.  Li Conductivity in Li x MPO 4 ( M = Mn , Fe , Co , Ni ) Olivine Materials , 2004 .

[50]  S. Pennycook,et al.  Vacancy-driven anisotropic defect distribution in the battery-cathode material LiFePO4. , 2011, Physical review letters.

[51]  L. Nazar,et al.  Small polaron hopping in Li(x)FePO4 solid solutions: coupled lithium-ion and electron mobility. , 2006, Journal of the American Chemical Society.

[52]  M. Alouani,et al.  Implementation of the projector augmented-wave LDA+U method: Application to the electronic structure of NiO , 2000 .

[53]  M. Wagemaker,et al.  A Kinetic Two‐Phase and Equilibrium Solid Solution in Spinel Li4+xTi5O12 , 2006 .

[54]  Yoyo Hinuma,et al.  Thermodynamic and kinetic properties of the Li-graphite system from first-principles calculations , 2010 .

[55]  Gerbrand Ceder,et al.  THE LI INTERCALATION POTENTIAL OF LIMPO4 AND LIMSIO4 OLIVINES WITH M = FE, MN, CO, NI , 2004 .

[56]  Ying Shirley Meng,et al.  First principles computational materials design for energy storage materials in lithium ion batteries , 2009 .

[57]  Thomas J. Richardson,et al.  Electron Microscopy Study of the LiFePO4 to FePO4 Phase Transition , 2006 .

[58]  A. Yamada,et al.  Experimental visualization of lithium diffusion in LixFePO4. , 2008, Nature materials.

[59]  Nathalie Ravet,et al.  Electroactivity of natural and synthetic triphylite , 2001 .

[60]  Peter R. Slater,et al.  Atomic-Scale Investigation of Defects, Dopants, and Lithium Transport in the LiFePO4 Olivine-Type Battery Material , 2005 .

[61]  John O. Thomas,et al.  Lithium extraction/insertion in LiFePO4: an X-ray diffraction and Mossbauer spectroscopy study , 2000 .

[62]  G. Henkelman,et al.  A climbing image nudged elastic band method for finding saddle points and minimum energy paths , 2000 .

[63]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[64]  G. Henkelman,et al.  Calculations of Li-Ion Diffusion in Olivine Phosphates , 2011 .

[65]  Masao Yonemura,et al.  Room-temperature miscibility gap in LixFePO4 , 2006, Nature materials.

[66]  L. Nazar,et al.  Nano-network electronic conduction in iron and nickel olivine phosphates , 2004, Nature materials.

[67]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[68]  Gerbrand Ceder,et al.  Configurational Electronic Entropy and the Phase Diagram of Mixed-Valence Oxides: The Case of Li$_x$FePO$_4$ , 2006 .

[69]  Venkat Srinivasan,et al.  Discharge Model for the Lithium Iron-Phosphate Electrode , 2004 .