Electrochemical and structural study of LiCoPO4-based electrodes

Bramnik, Natalia N.; Bramnik, Kirill G.; Buhrmester, Thorsten; Baehtz, Carsten; Ehrenberg, Helmut; Fueß, H.

doi:10.1007/s10008-004-0497-x

Cited by 131 publications

(76 citation statements)

References 11 publications

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“…7,8 However, the reported electrochemical performance of LCP, synthesized by many different routes, does not reach the theoretical specific capacity, shows low coulombic efficiency, and exhibits poor cycling stability. For example, Ni et al 9 synthetized carbon-coated LCP material by a sol gel route which gave a specific capacity of 131 mAh/g LCP at 0.1 C in the 1 st cycle and lost 25% of its initial capacity after only 40 cycles.…”

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Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Freiberg

Metzger

Haering

et al. 2014

J. Electrochem. Soc.

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Trimethylboroxine (TMB) is used as an additive in the electrolyte for improving the performance of LiCoPO 4 (LCP) in Li-ion batteries. In this work, the role and behavior of TMB are investigated by cyclic voltammetry (CV), impedance spectroscopy (EIS) and on line electrochemical mass spectroscopy (OEMS). It was found that TMB oxidizes from 4.6 V and a low amount in the electrolyte is necessary to obtain good performance. On one hand, its oxidation produces boron trifluoride (BF 3 ), phosphorylfluoride (POF 3 ) and carbanion (CH 3 -) linked to a huge increase in impedance. Based on these results, a complete oxidation mechanism is proposed. The catalytic effect of the TMB decomposition products on carbonate polymerization could enhance the performance of LCP. On the other hand, an unexplained water and/or HF release was detected. Further experiments need to be done. Rechargeable lithium batteries were first developed with lithium metal as a negative electrode (anode) and several positive electrode (cathode) materials like Li/MnO 2 1 or Li/LiTiS 2 . 2 Due to safety issues related to dendrite formation with lithium metal anode, the first Li-ion batteries were commercialized by Sony in 1991 using graphite anodes.3 Later on, layered-oxide based cathode materials like LiCoO 2 were developed, which have specific capacities and specific energies of ≈170 mAh/g LiCoO2 and ≈600 mWh/g LiCoO2 , respectively. In order to improve battery safety, cost and energy density, recent research has focused on new electrode materials. On the cathode side, numerous spinel structure materials were tested and showed good electrochemical performance. 4 In 1997, phospho-olivine cathode materials of the general formula LiMPO 4 (M = 3d-transition metal) emerged with the discovery of LiFePO 4 (LFP) by Goodenough's group, 5 which generally have more safety characteristics due to the strong P-O bond preventing O 2 release at high potential/temperature (problematic with layered oxides). So far, more than 1200 patents have been filed for phospho-olivines.6 LFP has a theoretical specific capacity of 171 mAh/g LFP and the oxidation from Fe II to Fe III takes place at 3.45 V, resulting in a specific energy of ≈590 mWh/g LFP . While offering improved safety, its specific energy is very similar to LiCoO 2 , so that with respect to energy density, LFP offers no improvement over LiCoO 2 .One approach toward improved energy density required for electric vehicle applications would be the use of LiCoPO 4 (LCP) cathode material, which promises a theoretical specific energy of ≈800 mWh/g LCP based on a charge/discharge voltage of ≈4.85 V vs. Li/Li + and a theoretical specific capacity of 167 mAh/g LCP . 7,8 However, the reported electrochemical performance of LCP, synthesized by many different routes, does not reach the theoretical specific capacity, shows low coulombic efficiency, and exhibits poor cycling stability. For example, Ni et al.9 synthetized carbon-coated LCP material by a sol gel route which gave a specific capacity of 131 mAh/g LCP at 0.1 C in the...

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confidence: 99%

Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Freiberg

Metzger

Haering

et al. 2014

J. Electrochem. Soc.

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“…23 However, this LiFePO 4 cathode is not suitable to attain the highenergy density batteries described above, because its voltage is insufficiently high. Many studies have been carried out on other olivine compounds such as LiMnPO 4 [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] and its utilization enables us to attain highenergy density batteries. Many strategies for the LiCoPO 4 cathode, similar to those of the LiFePO 4 cathode, have been proposed, because they present common problems that hinder their practical application: particle fining, [39][40][41] carbon coating of the particle surface, [42][43][44][45][46] and the cation substitution.…”

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Electrochemical and Magnetic Studies of Li-Deficient Li_1-xCo_1-xFe_xPO₄Olivine Cathode Compounds

Hanafusa

Oka

Nakamura

2014

J. Electrochem. Soc.

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Li-deficient olivine compounds, Li 1-x Co 1-x Fe x PO 4 (x < 0.15), were prepared by calcination of the sol-gel derived precursors in ambient atmosphere. They were almost single phase at x < 0.10 but some impurity phases were found at x > 0.10. The lattice parameters changed continuously with an increase in the Fe substitution. Their variation in the range of x < 0.10 roughly obeyed Vergard's law. From the 57 Fe Mössbauer spectrum at room temperature, it was shown that the introduced Fe took a trivalent highspin state in the olivine lattice. The temperature-dependent magnetic susceptibility exhibited that the Fe incorporation enhanced the antiferromagnetic ordering: the Neel temperature shifted higher. Furthermore, the electrochemical performances, such as cycling stability and rate capability, were improved significantly with an appropriate substitution (about 10%) with Fe 3+ . Consequently, the Fe 3+ incorporated compounds with Li deficiency as the charge compensation are thought to be good candidates as high-voltage cathode material, which may enhance the energy density of Li ion battery.

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“…The sol-gel technique in ethylene glycol [163,164] appeared to be a simple method to prepare submicron-sized carbon-coated LNP and LCP with only little dispersion in the size distribution. Bramnik et al [148] reported the effect of different synthesis routes on Li extraction-insertion from LiCoPO 4 ; samples prepared by SSR method at high temperature demonstrated unsatisfactory electrochemical performance [149], although some improvement was observed by a synthetic approach based on the precursor NH 4 CoPO 4 •H 2 O [162]. Surface modification of LCP particles was obtained via a thin layer of Al 2 O 3 deposited (*10 nm) by a sputtering method [158] or via a thin layer of LiFePO 4 (*4 nm) by SSR method [153], and will be discussed below.…”

Section: Olivine Frameworkmentioning

confidence: 99%

High Voltage Cathode Materials

Julien

Mauger

Zaghib³

et al. 2015

Rechargeable Batteries

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Electrochemical and structural study of LiCoPO4-based electrodes

Cited by 131 publications

References 11 publications

Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Electrochemical and Magnetic Studies of Li-Deficient Li_1-xCo_1-xFe_xPO₄Olivine Cathode Compounds

High Voltage Cathode Materials

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Electrochemical and structural study of LiCoPO4-based electrodes

Cited by 131 publications

References 11 publications

Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Anodic Decomposition of Trimethylboroxine as Additive for High Voltage Li-Ion Batteries

Electrochemical and Magnetic Studies of Li-Deficient Li1-xCo1-xFexPO4Olivine Cathode Compounds

High Voltage Cathode Materials

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Electrochemical and Magnetic Studies of Li-Deficient Li_1-xCo_1-xFe_xPO₄Olivine Cathode Compounds