Abstract The realization of thermally robust, polymer‐based radio‐frequency (RF) switches for flexible millimeter‐wave (mmWave) electronics is a long‐standing challenge due to inherent material instability. Here, a novel high‐performance, thermally stable polymer‐based non‐volatile analogue switch is reported, utilizing an Au/poly(1,3,5‐trimethyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3)/Au memristive structure. A gold filamentary conduction model is elucidated that governs the device's resistive switching, enabling analogue switching operations. Fabricated via a wafer‐scale compatible initiated chemical vapor deposition technique, the device overcomes the limitations of prior organic electronics, exhibiting notable high‐temperature stability with a projected state retention of over 10 years at 128.7 °C and robust endurance exceeding 1600 cycles. Furthermore, the switch demonstrates excellent RF performance suitable for mmWave applications, featuring a cutoff frequency of 5.38 THz, low insertion loss (<0.4 dB), high isolation (>18 dB) up to 20 GHz, and stable operation up to 67 GHz. Successful implementation on a flexible substrate confirms its mechanical resilience for wearable systems. This work establishes a viable pathway for robust, polymer‐based analogue switches in advanced flexible RF technologies.

Polymeric sulfur demonstrates immense capabilities as a promising active material for lithium–sulfur batteries (LSBs) owing to their ability to capture lithium polysulfides (LiPS) through the formation of covalent bonds. Herein, we demonstrate an ionic structured polymeric sulfur (IP-S) as a redox mediating matrix, which provides structural stability, an ionic conductive pathway, and a uniform distribution of active materials within the electrode. In particular, the cationic structure of IP-S was attributed to the facilitated LiPS conversion kinetics with the high utilization of sulfur. Consequently, the IP-S electrode delivered the high specific capacity of 1398.8 mAh gsulfur–1 with a low-capacity fading rate of 0.071% over 400 cycles. Moreover, with a high sulfur loading (6.87 mgsulfur cm–2), the IP-S electrode achieved a high initial capacity of 7.23 mAh cm–2. Therefore, this work provides the rational design of ionic structured polymeric sulfur for high performance LSBs as well as the correlation between the ionic structure and the electrochemical property.