This book presents original methods to facilitate the development of micro-mixed-potential-type nitrogen dioxide sensors, especially in the following aspects: (i) improvement of sensing performance of electrodes; (ii) enhancement of chemical activity of reaction interface; (iii) development of advanced flexible low-power-consumption mixed-potential-type YSZ-based nitrogen dioxide sensors. Miniaturized sensors have steadily emerged into the commercial marketplace as competitive alternatives for monitoring and controlling the pollution gas in automobile industry. Despite the great potential, the real-world applications for most conventional micro-nitrogen dioxide sensors are still limited due to insufficient sensitivity, unacceptable cost, and the lack of robustness under harsh environmental disturbances. To address the issue, micro-nitrogen dioxide sensors based on mixed potential solid electrolyte is an ongoing area of great academic and technological interest. This book is expected tobe a guide for researchers on the way forward to chase future horizons in the fields of instrumentation, electrochemistry and micro/nano-electronics.