Analysis of the size effect of LiMnPO4 particles on the battery properties by using STEM-EELS

Yoshida, Jun; Stark, M.A.; Holzbock, J.; Hüsing, Nicola; Nakanishi, Shinji; Iba, Hideki; Abe, Hiroya; Naito, Makio

doi:10.1016/j.jpowsour.2012.09.081

Cited by 57 publications

(39 citation statements)

References 18 publications

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“…In agreement with what has been previously observed, the addition of the phosphate ester based structure directing agent (SDA) Triton H-66® does not only lead to a decrease the particle size but also a change of the particle morphology can be observed. 14,16 Moreover, the addition of the SDA has a positive influence on the formation of structure defect free LiMn 0.8 Fe 0.2 PO 4 . It has been assumed, that the faster incorporation of Mn 2+ in the phosphoolivine structure locks the defect structure and does not allow any further reassembling and depressing the disorder.…”

Section: Scanning Electron Microscopymentioning

confidence: 99%

Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent

Schoiber

Tippelt

Redhammer

et al. 2015

Crystal Growth & Design

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As confirmed by ion coupled plasma-mass spectrometry and powder X-ray diffraction, stoichiometrically pure samples of olivine type LiFe 0.2 Mn 0.8 PO 4 in the presence of a phosphoric acid ester based structure directing agent have been prepared. A Rietveld analysis of X-ray and n 0 diffraction data suggests that the solids are largely free of defect occupation of Fe at the lithium sites. This is confimed by 57 Fe-Mößbauer spectroscopic investigations. The use of the structure directing surfactant results in significantly higher specific surface areas (SSA) and smaller particle sizes as compared to samples prepared without using a surfactant. In using NO 3 -salt educts or different surfactants a further increase in SSA but at a cost of lower stoichiometric lithium contents can be achieved. INTRODCUTIONOlivine type lithium transition metal phosphates LiMPO 4 (M = Fe, Mn, Co, Ni) are amongst the most promising candidates for cathode materials in next-generation rechargeable lithium-ion batteries. For this reason they have been in the focus of intense research activities in the past one and a half decades. 1─4 One of the most important development goals is to improve the charge/discharge capacity by a proper choice of the composition and the structure of the battery materials. The theoretical maximum capacity of LiFePO 4 as a cathode material is 170 mAh/g. 5 Values closely approaching this upper limit have been reported for materials which have been prepared via solid state reaction or with hydrothermal synthesis methods. 4 In contrast partially manganese substituted materials of type LiFe 1-x Mn x PO 4 prepared in hydrothermal reactions often show disappointing electrochemical properties significantly below this value. 6 This is often attributed to lattice defects, like Fe/Li interchange (which is often also called an 'anti-site defect') or an surplus of M 2+ -ions (M = Me, Fe) at lithium sites (which are also called M1 sites in the olivine structure, as compared to the positions of the transition metal which are called M2 sites) (see figure 1). Such defects presumably block Li ions in the diffusion pathway. 7 Theoretical considerations and model calculations suggest that the most favourable defect occurring in LiMPO 4 (M= Fe, Mn, Co, Ni) olivines is the Li + /M 2+ interchange (anti−site defect), with an occurrence lower than 2%. 8 Hereby is the actual amount expected to largely depend on synthesis conditions especially the reaction temperature. Systems with M = Fe or Co, are expected to be especially prone to Li + /M 2+ interchange defects. 9 Whereas the influence of experimental conditions on structural defects for the end members LiMnPO 4 and LiFePO 4 of the solid solution series LiMn 1-x Fe x PO 4 have already been investigated in detail 8-12 much less is documented for mixed stoichiometries such as LiMn 1-x Fe x PO 4 . 13 In a very recent work Jensen et al. have investigated the structural nature of these lattice defects in LiFe 1-x Mn x PO 4 materials. 6 From combined X-ray diffraction (XRD), neutron-diffract...

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Section: Scanning Electron Microscopymentioning

confidence: 99%

Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent

Schoiber

Tippelt

Redhammer

et al. 2015

Crystal Growth & Design

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“…In an effort to improve the rate and cyclic performances of LiMnPO 4 , the employed methods include reducing the LiMnPO 4 crystal size to nano-scale [10][11][12], coating LiMnPO 4 crystallites with carbon [13,14], and substituting Mn 2+ with other cations such as Fe 2+ , Mg 2+ , Ti 2+ , Ca 2+ , Zr 4+ , or Cu 2+ [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. These methods may enhance transport properties of the material's electron and Li ion, and consequently make LiMnPO 4 obtain the outstanding electrochemical performance.…”

Section: Introductionmentioning

confidence: 99%

Synergetic Fe substitution and carbon connection in LiMn1−xFexPO4/C cathode materials for enhanced electrochemical performances

Yan

Wang

et al. 2015

Journal of Alloys and Compounds

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“…Numerous attempts have been made to improve the electrochemical performance of LiMnPO 4 , including reducing crystal size to nanoscale [10][11][12], coating conductive agent such as carbon [12,13] and doping cation such as Fe 2+ , Mg 2+ , Ti 2+ , Ca 2+ , Zr 4+ , or Cu 2+ [14][15][16][17][18][19][20][21][22][23][24][25][26]. These approaches could effectively improve the electrons conductivities and Li + ions transport properties of LiMnPO 4 and thus enhance its electrochemical performances.…”

Section: Introductionmentioning

confidence: 99%

Enhanced kinetic behaviors of LiMn0.5Fe0.5PO4/C cathode material by Fe substitution and carbon coating

Yan

Wang

et al. 2015

J Solid State Electrochem

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The LiMn 0.5 Fe 0.5 PO 4 /C nanocrystallites with a uniform size (∼50 nm) are successfully prepared by employing a facile solvothermal method at 180°C. Amphiphilic carbonaceous material (ACM) is chosen as the carbon precursor and forms a homogeneous carbon layer covering the LiMn 0.5 Fe 0.5 PO 4 particles. The asprepared LiMn 0. 5 Fe 0. 5 PO 4 /C sample, with a high Brunauer-Emmett-Teller (BET) surface area of 69.3 m 2 g −1 , is used as the cathode material for lithiumion batteries (LIBs) and delivers a reversible capacity of 158 mAh g −1 at 0.05 C. It shows remarkable rate capability with discharge capacities of 130 mAh g −1 at 1 C, 105 mAh g − 1 at 10 C and 99 mAh g − 1 at 30 C. Meanwhile, the material maintains 121 mAh g −1 at 1 C after 150 cycles with 93 % capacity retention. The kinetic behaviors of LiMn 0.5 Fe 0.5 PO 4 /C sample are investigated by high throughout cyclic voltammetry. The small particle size, partial Fe substitution, and homogeneous carbon coating make a synergetic effect on enhancing the sample's electrochemical properties.

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Analysis of the size effect of LiMnPO4 particles on the battery properties by using STEM-EELS

Cited by 57 publications

References 18 publications

Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent

Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent

Synergetic Fe substitution and carbon connection in LiMn1−xFexPO4/C cathode materials for enhanced electrochemical performances

Enhanced kinetic behaviors of LiMn0.5Fe0.5PO4/C cathode material by Fe substitution and carbon coating

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Analysis of the size effect of LiMnPO4 particles on the battery properties by using STEM-EELS

Cited by 57 publications

References 18 publications

Defect and Surface Area Control in Hydrothermally Synthesized LiMn0.8Fe0.2PO4 Using a Phosphate Based Structure Directing Agent

Defect and Surface Area Control in Hydrothermally Synthesized LiMn0.8Fe0.2PO4 Using a Phosphate Based Structure Directing Agent

Synergetic Fe substitution and carbon connection in LiMn1−xFexPO4/C cathode materials for enhanced electrochemical performances

Enhanced kinetic behaviors of LiMn0.5Fe0.5PO4/C cathode material by Fe substitution and carbon coating

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Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent

Defect and Surface Area Control in Hydrothermally Synthesized LiMn_0.8Fe_0.2PO₄ Using a Phosphate Based Structure Directing Agent