A new class of amorphous cathode active material LixMyPOz (M = Ni, Cu, Co, Mn, Au, Ag, Pd)

Sabi, Yuichi; Sato, Susumu; Hayashi, Saori; Furuya, Tatsuya; Kusanagi, Susumu

doi:10.1016/j.jpowsour.2014.02.021

Cited by 14 publications

(12 citation statements)

References 12 publications

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“…In addition, Sabi et al have reported the preparation of the amorphous positive electrode films LixMyPOz (M = Ni, Co, etc.) and the fabrication of thin-film type all-solid-state batteries using a sputtering technique [16]. The thin-film type all-solid-state batteries operated as secondary batteries and showed the large capacity of 330 mAh g -1 with the relatively high average discharge voltage of ca.…”

Section: Introductionmentioning

confidence: 99%

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

et al. 2018

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Amorphous LiCoO2-based positive electrode materials are synthesized by a mechanical milling technique. As a lithium oxy-acid, Li2SO4, Li3PO4, Li3BO3, Li2CO3, and LiNO3 are selected and milled with LiCoO2. XRD patterns indicate that reaction between LiCoO2 and these lithium oxy-acids proceeds. Amorphization mainly occurs, and several broad peaks attributable to cubic LiCoO2 are observed in all the samples. These amorphous active materials show mixed conductivities of electron and lithium ion. All-solid-state cells using the prepared amorphous active materials and the Li2.9B0.9S0.1O3.1 glass-ceramic electrolyte are fabricated and their charge-discharge properties are examined. The cells with only the 80LiCoO2·20Li2SO4 (mol%) and the 80LiCoO2·20Li3PO4 active materials function as secondary batteries. This is because higher lithium ionic conductivities are obtained in the 80LiCoO2·20Li2SO4 and 80LiCoO2·20Li3PO4 active materials than in the others. The largest capacity is obtained in the cell with the 80LiCoO2·20Li2SO4 active material because of its good formability and high lithium ionic conductivity. In addition, the cell with the 80LiCoO2·20Li2SO4 positive electrode active material shows the better cycle and rate performance than that with the crystalline LiCoO2. It is noted that the amorphization with lithium oxy-acids is a promising technique for achieving a novel active material with better electrochemical performance.

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Section: Introductionmentioning

confidence: 99%

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

et al. 2018

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“…Further work associated with solid-state batteries examined a sputtered thin amorphous layer of Li 3 PO 4 on LiNiO 2 . 30 A question arises; amorphous Li 3 PO 4 cannot be obtained by mechanical milling, as shown in Figure 1 a, and crystalline Li 3 PO 4 only shows a reduction in the crystallinity with milling. Notably, synchrotron XRD data show a higher crystallinity for the rocksalt phase for x = 0.2 when compared with that of x = 0 without Li 3 PO 4 ( Supporting Figure S4 ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…They proposed that nanosize LiCoO 2 was embedded in an amorphous matrix of Li 2 SO 4 , forming a nanocomposite. Further work associated with solid-state batteries examined a sputtered thin amorphous layer of Li 3 PO 4 on LiNiO 2 . A question arises; amorphous Li 3 PO 4 cannot be obtained by mechanical milling, as shown in Figure a, and crystalline Li 3 PO 4 only shows a reduction in the crystallinity with milling.…”

Section: Results and Discussionmentioning

confidence: 99%

Nanostructured LiMnO₂ with Li₃PO₄ Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox

et al. 2020

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Nanostructured LiMnO 2 integrated with Li 3 PO 4 was successfully synthesized by the mechanical milling route and examined as a new series of positive electrode materials for rechargeable lithium batteries. Although uniform mixing at the atomic scale between LiMnO 2 and Li 3 PO 4 was not anticipated because of the noncompatibility of crystal structures for both phases, our study reveals that phosphorus ions with excess lithium ions dissolve into nanosize crystalline LiMnO 2 as first evidenced by elemental mapping using STEM-EELS combined with total X-ray scattering, solid-state NMR spectroscopy, and a theoretical ab initio study. The integrated phase features a low-crystallinity metastable phase with a unique nanostructure; the phosphorus ion located at the tetrahedral site shares faces with adjacent lithium ions at slightly distorted octahedral sites. This phase delivers a large reversible capacity of ∼320 mA h g –1 as a high-energy positive electrode material in Li cells. The large reversible capacity originated from the contribution from the anionic redox of oxygen coupled with the cationic redox of Mn ions, as evidenced by operando soft XAS spectroscopy, and the superior reversibility of the anionic redox and the suppression of oxygen loss were also found by online electrochemical mass spectroscopy. The improved reversibility of the anionic redox originates from the presence of phosphorus ions associated with the suppression of oxygen dimerization, as supported by a theoretical study. From these results, the mechanistic foundations of nanostructured high-capacity positive electrode materials were established, and further chemical and physical optimization may lead to the development of next-generation electrochemical devices.

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“…To date, the majority of reported active materials are crystalline in nature, while those of amorphous active materials are limited. However, such amorphous materials have many advantages, − including additional stable sites for cations due to their open and random structures, and so this can lead to larger capacities and improved cyclabilities. As such, we expect that the energy densities of active materials could be improved through amorphization.…”

Section: Introductionmentioning

confidence: 99%

Amorphization of Sodium Cobalt Oxide Active Materials for High-Capacity All-Solid-State Sodium Batteries

et al. 2018

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Amorphous Na0.7CoO2–Na x MO y (M = N, S, P, B, or C) positive electrode active materials were synthesized by a mechanochemical technique to achieve high capacities and improved cyclabilities owing to their open and random structures. As none of the X-ray diffraction peaks are attributable to the starting materials, it was clear that the reaction between Na0.7CoO2 and Na x MO y had been successful. The prepared Na0.76Co0.8N0.2O2.2 (80Na0.7CoO2·20NaNO3 (mol %)) was easily densified by pressing at room temperature, and then applied as a positive electrode in bulk-type all-solid-state sodium cells (Na15Sn4/Na3PS4 glass-ceramic/Na0.7CoO2–Na x MO y ). The cell based on the Na0.76Co0.8N0.2O2.2 active material without any conductive additives in an ultrathick positive electrode layer (∼50 μm thickness) operated as a secondary battery at 25 °C. The average discharge voltage was 2.9 V, and the initial discharge capacity was 70 mAh g−1 of the positive electrode. This cell exhibited a higher discharge voltage and a larger capacity than cells employing crystalline Na0.7CoO2 or milled Na0.7CoO2 as the positive electrode. The electrochemical properties of Na0.7CoO2 were therefore improved by amorphization with NaNO3. Furthermore, the cell with the composite electrode containing a conducting additive gave a discharge capacity of 170 mAh g−1 of Na0.76Co0.8N0.2O2.2, which is the highest reported to date for all-solid-state sodium cells based on oxide positive electrodes. Therefore, the amorphization of layered transition-metal oxides with sodium oxy-acids is an effective way to achieve novel active materials with high capacities.

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A new class of amorphous cathode active material LixMyPOz (M = Ni, Cu, Co, Mn, Au, Ag, Pd)

Cited by 14 publications

References 12 publications

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

Nanostructured LiMnO₂ with Li₃PO₄ Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox

Amorphization of Sodium Cobalt Oxide Active Materials for High-Capacity All-Solid-State Sodium Batteries

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A new class of amorphous cathode active material LixMyPOz (M = Ni, Cu, Co, Mn, Au, Ag, Pd)

Cited by 14 publications

References 12 publications

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

Nanostructured LiMnO2 with Li3PO4 Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox

Amorphization of Sodium Cobalt Oxide Active Materials for High-Capacity All-Solid-State Sodium Batteries

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Nanostructured LiMnO₂ with Li₃PO₄ Integrated at the Atomic Scale for High-Energy Electrode Materials with Reversible Anionic Redox