Quantitative Visualization of Salt Concentration Distributions in Lithium-Ion Battery Electrolytes during Battery Operation Using X-ray Phase Imaging

Abstract

A fundamental understanding of concentrations of salts in lithium-ion battery electrolytes during battery operation is important for optimal operation and design of lithium-ion batteries. However, there are few techniques that can be used to quantitatively characterize salt concentration distributions in the electrolytes during battery operation. In this paper, we demonstrate that in operando X-ray phase imaging can quantitatively visualize the salt concentration distributions that arise in electrolytes during battery operation. From quantitative evaluation of the concentration distributions at steady states, we obtained the salt diffusivities in electrolytes with different initial salt concentrations. Because of no restriction on samples and high temporal and spatial resolutions, X-ray phase imaging will be a versatile technique for evaluating electrolytes, both aqueous and nonaqueous, of many electrochemical systems.

In Situ Electrospinning Synthesis of N‐Doped C Nanofibers with Uniform Embedding of Mn Doped MFe1−xMnxPO4 (M = Li, Na) as a High Performance Cathode for Lithium/Sodium‐Ion Batteries

“…The increased R ct can be related to the existence of substituted ion on the surface of the crystals, which restrained the charge transmission on the surface of active materials. Figure 5d shows the relationship between the Z re and angular frequency in the low frequency, and the slope of the beeline is the σ ω according to the above Equation (4). The calculated diffusion coefficient values of the Li ions (D Li+ ) based on Equation (5) are displayed in Table S3 (Supporting Information).…”

“…many arbitrary portable applications (e.g., laptop, mobile phone, and remote control) and new energy vehicles due to their superior advantages, such as high energy density, long cycle life, low self-discharge rate, and environmental friendliness. [1][2][3][4][5] Among the components of LIBs, the cathode materials play an important and key role for reversible high performances and economic costs of LIBs. [6][7][8][9] Olivine crystalline phosphate is a considerable candidate as the cathode material for LIBs with the advantages of low toxicity, safety, and low cost.…”

Feasibility study of interferometric phase-contrast X-ray imaging using the hard-X-ray free-electron laser of the SPring-8 Angstrom Compact Free-Electron Laser

“…Phase-contrast X-ray imaging using a crystal X-ray interferometer (XI) (Bonse & Hart, 1965;Momose et al, 1996) has the highest sensitivity among phase-sensitive X-ray imaging methods (Yoneyama et al, 2008(Yoneyama et al, , 2015, and the density resolution of three-dimensional observation can reach 0.5 mg cm À3 (Yoneyama et al, 2013). We have studied many biological samples, for example soft tissues such as the kidney, brain and heart (Takeda et al, 2002;Yoneyama et al, 2005;Noda-Saita et al, 2006), embryos (Yamada et al, 2012), energy materials such as methane hydrates (Takeya et al, 2006), and industrial products such as lithium ion batteries (Takamatsu et al, 2018), achieved by taking advantage of the high sensitivity of XI. In addition, we developed X-ray thermography (Yoneyama et al, 2018) for detecting changes in temperature caused by thermal expansion, and we successfully performed time-resolved observation of thermal flow in heated water with a 1.3 s interval.…”

Direct Observation of Ion Concentration Distribution in All-Solid-State Rechargeable Battery Using <i>operando</i> X-ray Radiography and Silver-Ion Conductor

“…Regarding the characteristic mechanism of the battery cell, inhomogeneous concentration distribution of the carrier ion in the composite electrode [5][6][7][8][9] and electrolyte 10,11 in a conventional lithiumion battery that employs a liquid electrolyte has been reported. The electrode of a lithium-ion battery is composed of active material, conductive carbon, and binder.…”

“…Consequently, the concentration of cations increases near the cathode to maintain local electrical neutrality, inducing a salt concentration gradient in the electrolyte. 10,11 Krachkovskiy, et al analyzed the distribution of salt concentration in an Li « 1 mol dm ¹3 LiPF 6 (ethylene carbonate + dimethyl carbonate 1:1 v/v) « C cell via 7 Li-and 19 F-nuclear magnetic resonance (NMR). A concentration distribution of 0.78-1.27 mol dm ¹3 along a perpendicular direction to plane of electrolyte between electrodes was observed in the 1 mol dm ¹3 LiPF 6 liquid electrolyte.…”