Imaging Sensor for the Detection of the Flow Battery Via Weak Value Amplification

Abstract

Flow battery electrodes are vital for performing redox reactions, and an indepth understanding of reaction kinetics and spatial distribution differences in electrodes is very important for improving the efficiency of electrochemical reactions. In this study, a reflection-type phase-sensitive weak measurement imaging system was developed for the detection of flow batteries. The phase difference between two polarization components in total internal reflection caused by electrode redox processes was measured by weak value amplification. The resulting refractive index resolution of the imaging system was estimated to be 2.8−4.2 × 10 −6 RIU. The real-time monitoring ability of the system was demonstrated by linear sweep voltammetry tests of vanadium redox batteries. Compared to traditional optical methods, the proposed weak measurement imaging sensor did not require coating, as it can be used in acid electrolytes of vanadium flow batteries. Meanwhile, the weak value amplification effect led to a higher resolution than the total internal reflection system shown in our previous work, thereby resulting in more accurate detection of electrochemical reactions. In sum, the proposed sensor looks very promising for the detection of electrochemical reactions in flow batteries, water splitting, electrochemical corrosion, and electrocatalysis.

In Situ Mapping of Activity Distribution of V(II)/V(III) and Onset Potential Distribution of Hydrogen Evolution Side Reaction in Vanadium Flow Batteries

“…In existing studies, under the condition of WVA, the relationship between light intensity and phase difference can be expressed as: [ 32 ] $$$$\begin{equation}I \approx 2si{n}^2\left( {t{w}_0 + \varepsilon - \frac{\varphi }{2}} \right){\mathrm{\tau \Delta \ }} \ll 1\end{equation}$$$$ I is the relative light intensity (LI), τ is the coupling intensity, w 0 is the optical frequency, φ is the phase difference, ε ≪ 1 may make post‐selected states almost orthogonal to pre‐selected states, τΔ ≪ 1 weak coupling is easier to realize, satisfying the condition of WVA.…”

“…The WMi sensing system operates based on the weak value amplification (WVA) technology and establishes a quantitative relationship between the distribution of light intensity and phase difference, the distribution of light intensity and current density, and the distribution of light intensity and HER onset potential. [33] In existing studies, under the condition of WVA, the relationship between light intensity and phase difference can be expressed as: [32] www.small-methods.com…”

“…[29][30][31] As the study progressed, we replaced the TIRi method with a more sensitive weak measurement imaging (WMi) method, which enabled a more sensitive detection of vanadium flow battery positive distribution. [32] Herein, based on prior research by our research group, this paper employs the WMi method to investigate the activity distribution of V(II)/V(III) and the hydrogen evolution side reaction initiation potential in VFBs. The proposed method provides a new characterization technique for further exploring the negative reaction mechanism of VFBs, facilitating the development of VFBs with superior performance and fewer side effects.…”

“…[ 29–31 ] As the study progressed, we replaced the TIRi method with a more sensitive weak measurement imaging (WMi) method, which enabled a more sensitive detection of vanadium flow battery positive distribution. [ 32 ]…”

Demonstration of a New Characterization Method for Weak Measurement

“…Since 2010, relevant theories have shown that the weak measurement technology exhibits more obvious detection advantages in the frequency domain than the other fields ( Brunner and Simon, 2010 ; Xu et al, 2013 ). In 2015, our group first proposed a novel optical frequency domain weak measurement system with universal value, which has shown amazing potential in the field of biomolecular detection ( Zhang et al, 2016 ; Li et al, 2017 ; Li et al, 2018 ; Xu et al, 2018 ; Xu et al, 2019a ; Xu et al, 2019b ; Xu et al, 2021 ).…”