Hydrogels are widely used in flexible aqueous batteries due to their liquid‐like ion transportation abilities and solid‐like mechanical properties. Their potential applications in flexible and wearable electronics introduce a fundamental challenge: how to lower the freezing point of hydrogels to preserve these merits without sacrificing hydrogels' basic advantages in low cost and high safety. Moreover, zinc as an ideal anode in aqueous batteries suffers from low reversibility because of the formation of insulative byproducts, which is mainly caused by hydrogen evolution via extensive hydration of zinc ions. This, in principle, requires the suppression of hydration, which induces an undesirable increase in the freezing point of hydrogels. Here, it is demonstrated that cooperatively hydrated cations, zinc and lithium ions in hydrogels, are very effective in addressing the above challenges. This simple but unique hydrogel not only enables a 98% capacity retention upon cooling down to −20 °C from room temperature but also allows a near 100% capacity retention with >99.5% Coulombic efficiency over 500 cycles at −20 °C. In addition, the strengthened mechanical properties of the hydrogel under subzero temperatures result in excellent durability under various harsh deformations after the freezing process.

By virtue of the well‐developed micro‐ and nanofabrication technologies and rapidly progressing surface functionalization strategies, silicon‐based devices have been widely recognized as a highly promising platform for the next‐generation lab‐on‐a‐chip bioanalytical systems with a great potential for point‐of‐care medical diagnostics. Herein, an overview of the latest advances in silicon‐based integrated optofluidic label‐free biosensing technologies relying on the efficient interactions between the evanescent light field at the functionalized surface and specifically bound analytes is presented. State‐of‐the‐art technologies demonstrating label‐free evanescent wave‐based biomarker detection mainly encompass three device configurations, including on‐chip waveguide‐based interferometers, microring resonators, and photonic‐crystal‐based cavities. Moreover, up‐to‐date strategies for elevating the sensitivities and also simplifying the sensing processes are discussed. Emerging laboratory prototypes with advanced integration and packaging schemes incorporating automatic microfluidic components or on‐chip optoelectronic devices lead to one significant step forward in real applications of decentralized diagnostics. Besides, particular attention is paid to currently commercialized label‐free optical bioanalytical models on the market. Finally, the prospects are elaborated with several research routes toward chip‐scale, low‐cost, highly sensitive, multi‐functional, and user‐friendly bioanalytical systems benefiting to global healthcare.