Engineering the electric double layer (EDL) next to the electrode surface as an impedance-dominating location inside an ionogel provides us an opportunity to detect sound underwater, especially sound from different directions. In response to these vector stimuli, subtle changes in the interface/EDL were easily captured by high-frequency alternating current (AC) modulations. In contrast to capacitive mechanisms under direct current (DC) operations, this AC mode generates an electric field at the interface which is orders of magnitude weaker than its DC counterpart. This removes any electrochemical reaction in the electrolytic environment, resulting in an exceptional signal-to-noise ratio (SNR) over 3000 min of continuous operations. Moreover, this ionogel-based microphone is found to be responsive to the whole range of low-frequency sounds, producing 60 dB (1000 times) stronger signals than the commercial hydrophone. Another unique feature of this microphone is its directivity even when the wavelength of the incoming sound far exceeds the size of the device, filling a property gap that affects the latest piezoelectric ceramic-based sound navigation ranging (SONARs).

中文翻译：

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Ionogel麦克风具有定向性和出色的稳定性，可检测水下声音

将电离层旁边的电双层（EDL）设计为离子凝胶内部的阻抗主导位置，为我们提供了机会来检测水下声音，尤其是来自不同方向的声音。响应这些矢量刺激，可以通过高频交流电（AC）调制轻松捕获界面/ EDL中的细微变化。与直流（DC）操作下的电容性机制相反，此AC模式在界面处产生的电场要比其DC对应物弱几个数量级。这样可以消除电解环境中的任何电化学反应，从而在连续运行3000分钟后产生出色的信噪比（SNR）。而且，发现这种基于离子凝胶的麦克风对整个低频声音都具有响应能力，产生比商用水听器强60 dB（1000倍）的信号。该麦克风的另一个独特功能是即使在传入声音的波长远远超过设备尺寸的情况下，其指向性也很明显，从而填补了影响最新基于压电陶瓷的声音导航测距（SONAR）的特性差距。