Internal resistance mapping preparation to optimize electrode thickness and density using symmetric cell for high-performance lithium-ion batteries and capacitors

Kisu, Kazuaki; Aoyagi, Shintaro; Nagatomo, Haruka; Iwama, Etsuro; Reid, McMahon Thomas Homer; Naoi, Wako; Naoi, Katsuhiko

doi:10.1016/j.jpowsour.2018.05.083

Cited by 55 publications

(36 citation statements)

References 19 publications

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“…Such results indicate that the creation of vacancies in M2 sites resulting from the oxidation/migration of Fe ions enhances the Li + diffusivity within LCFP crystal, unlike previous reports which suggest the enhancement of Li + mobility due to the vacancies in Li (M1) sites. 16,21 EIS analysis using symmetric cells 26 (see Figure S6) shows that the pristine LCFP shows higher impedance behavior than air-annealed LCFP (with Fe 3+ -rich surface). Both the charge transfer and mass transport processes were improved for Fe 3+ -rich LCFP: the relevant absolute impedance becomes roughly 1/10 for the charge transfer process and 1/5 for the diffusion process when moving from pristine LCFP to air-annealed LCFP.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

Okita¹,

Kisu²,

Iwama³

et al. 2018

Chem. Mater.

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Factors affecting the cyclability of the Fesubstituted LiCoPO 4 (LiCo 0.8 Fe 0.2 PO 4 , LCFP) material were elucidated, including both the structural and electrode/ electrolyte stability. Electrochemical characterization of the synthesized LCFP nanoparticles lends clear evidence for improved electrochemical stability of LCP, as well as enhanced rate capability, with Fe 3+ substitution. Surface analysis using X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) suggest that Fe enrichment on the surface of LCFP occurs through the oxidation of Fe 2+ into Fe 3+ in the synthesis process. The Fe 3+rich phase on the LCP surface enhances the stability of the delithiated phase, preventing oxidative reactions with electrolytes during high-voltage operation. This surface protection persists as long as the electrochemical reduction of Fe 3+ is avoided by ensuring that the full range of operating voltages lie above the Fe 3+ /Fe 2+ redox potential. Our findings may offer new approaches to stabilize the structure of LCP and other high-voltage positive electrodes for use in 5 V-class Li-ion batteries.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

Okita¹,

Kisu²,

Iwama³

et al. 2018

Chem. Mater.

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“…Clearly visible semicircle is typically associated with charge‐transfer resistance R ct . Before concluding the effect of conductive additives on the charge‐transfer resistance, it should be noted that the size of the semicircle in Nyquist plot is inversely proportional to the density of the electrode coating . Therefore, for an adequate assessment, it is correct to compare electrodes with approximately the same density (and thickness).…”

Section: Resultsmentioning

confidence: 99%

On the Use of Carbon Nanotubes in Prototyping the High Energy Density Li‐ion Batteries

et al. 2020

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This article is devoted to the laboratory technology aspects of high areal capacity electrode (more than 5 mAh cm−2) fabrication using carbon nanotubes (CNTs) as conductive additives and LiFePO4 as an active material. The influence of electrode slurry rheological properties and electrode composition on its areal (mAh cm−2), volumetric (mAh cm−3), and gravimetric (mAh g−1) capacity, and C‐rate performance has been studied. Using the small‐angle neutron scattering technique, it is shown that the CNT network embedded in the electrode layer provides greater wettability by an electrolyte compared with carbon black used as conductive additive. The practical applicability of the considered electrode technology is approved on a pouch cell prototype with a capacity of approximately 1.9 Ah and specific energy density of 150 Wh kg (cell)−1/295 Wh L (cell)−1.

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“…However, the mass specific capacity is affected by the high mass loading. The higher mass loadings in our electrodes were obtained via an intense densification approach that led to an enhanced CNT connection and larger specific surface areas (Figure S16a, Supporting Information) . They enhanced the conductivity of the electrodes, facilitated the charge transfer process, provided more active sites for electrochemical reactions and a decreased R ct value.…”

Section: Resultsmentioning

confidence: 99%

Reticulate Dual‐Nanowire Aerogel for Multifunctional Applications: a High‐Performance Strain Sensor and a High Areal Capacity Rechargeable Anode

Wang

Chen

et al. 2019

Adv Funct Materials

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Nanowire aerogels (NWAs) are highly versatile and used in many applications. However, most synthesized NWAs are composed of single components that may produce unsatisfactory aggregated performance in mechanical strength, conductivity, and electrochemistry. To address this issue, a reticulate dual-nanowire aerogel (rDNWA) composed of FeS 2 nanowires and carbon nanotubes (CNTs) via a simple solvothermal method is synthesized. The rDNWA possesses excellent compressibility (modulus of 1.32 MPa), good conductivity (0.65 S cm −1 ), and high porosity (>98%). It can be applied as a high-performance strain sensor with good sensitivity (Gauge Factor = 1.69) and enhanced stability. It can be densified to yield a high areal capacity of 10.0 mAh cm −2 and a high mass loading of 14.4 mg cm −2 after 100 cycles. As a freestanding anode for lithium ion battery (LIB), it exhibits a high specific mass capacity of 1031 mAh g −1 after 100 cycles at a current density of 100 mA g −1 and retains it to 729 mAh g −1 at a current density of 500 mA g −1 after 400 cycles. The outstanding overall performance of the hybrid aerogel is derived from the synergistic effect of intertwined CNTs and FeS 2 nanowires and can be extended to fabricate NWAs with novel multifunctional capabilities.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201807467. management, sensing, catalysis, etc. [1][2][3][4][5][6][7] SNWAs have been constructed from metal (Cu, Ag, Pd) nanowires, [2,[8][9][10][11] metal oxide (TiO 2 , MnO 2 , K 2−x Mn 8 O 16 ) nanowires, [5,[12][13][14] and other inorganic nanowires (Silica, C, SiC) [4,[15][16][17] and they are all composed of single nanowires that often constrained them to a single outstanding performance in say either the mechanical strength, conductivity, or electrochemical property (capacity, stability, and rate performance for a lithium ion battery (LIB)) but unsatisfactory when their collective capabilities are considered. For example, the Cu NWAs reported by Jung et al. [9] have superior conductivity (116 S cm −1 ) but due to the weak Van der Waals forces its mechanical strength is relatively low (Young's modulus: 1.2 kPa). The MnO 2 NWA synthesized by Long et al. [14] is intrinsically nonconductive even though its 1230 mAh g −1 theoretical capacity for an LIB is high. Carbon nanotube (CNT) aerogels [4] possess a relatively low specific capacity (372 mAh g −1 ) for an LIB despite being highly compressible with an excellent mechanical strength. Typically, most SNWAs are unable to concurrently satisfy several material stipulations of strength, conductivity, active electrochemistry, strain sensing, etc., required in a multifunctional application.To address this issue, much effort has been focused on the fabrication of reticulate NWAs with multicomponents. The mechanical blending of nonconductive nanowires with conductive materials (graphene, for example) during a preparation process (via a sol-gel method) is an effective way to improve their conductivity. ...

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Internal resistance mapping preparation to optimize electrode thickness and density using symmetric cell for high-performance lithium-ion batteries and capacitors

Cited by 55 publications

References 19 publications

Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

On the Use of Carbon Nanotubes in Prototyping the High Energy Density Li‐ion Batteries

Reticulate Dual‐Nanowire Aerogel for Multifunctional Applications: a High‐Performance Strain Sensor and a High Areal Capacity Rechargeable Anode

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Internal resistance mapping preparation to optimize electrode thickness and density using symmetric cell for high-performance lithium-ion batteries and capacitors

Cited by 55 publications

References 19 publications

Stabilizing the Structure of LiCoPO4 Nanocrystals via Addition of Fe3+: Formation of Fe3+ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

Stabilizing the Structure of LiCoPO4 Nanocrystals via Addition of Fe3+: Formation of Fe3+ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

On the Use of Carbon Nanotubes in Prototyping the High Energy Density Li‐ion Batteries

Reticulate Dual‐Nanowire Aerogel for Multifunctional Applications: a High‐Performance Strain Sensor and a High Areal Capacity Rechargeable Anode

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Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation

Stabilizing the Structure of LiCoPO₄ Nanocrystals via Addition of Fe³⁺: Formation of Fe³⁺ Surface Layer, Creation of Diffusion-Enhancing Vacancies, and Enabling High-Voltage Battery Operation