RheoPad, based on our proprietary nanorheology-enabled two-phase/dual-mode passive direct cooling technology, is designed to work seamlessly with mobile devices such as mobile phones, laptops, tablet PCs, game consoles, power banks, etc. Under passive direct liquid-cooling (DLC) mode, the effectiveness of our RheoPad is further enhanced that can remove the heat within the devices even more quickly and efficiently when the devices are running multiple apps that require high computational resources and power. Compared to the other conventional approaches and existing solutions, the passive cooling technology provides unprecedented thermal dissipation performance while extending the battery life and endurance by >20%. RheoPad represents an advanced two-phase direct liquid cooling solution that uses capillary action within a porous structure to manage high-density heat, often utilized in high-performance electronics and AI servers. The liquid in the pores turns into vapor, absorbing a high amount of latent heat. This vaporized fluid then escapes or condenses, removing the heat from the heat sink. This method provides superior cooling efficiency, often outperforming single-phase air or liquid cooling by maintaining high thermal performance while maintaining low thermal resistance for high-power workloads.