Membrane-encapsulated, moisture-desorptive passive cooling for high-performance, ultra-low-cost, and long-duration electronics thermal management

Passive thermal management strategies are one of the most promising ways to reduce energy consumption for intermittent heat dissipation. However, the existing strategies encounter tough obstacles on their way to commercialization due to their low efficiencies and high costs. Herein, we propose a passive thermal management strategy that relies on moisture desorption from hygroscopic salt solutions through a protective membrane that only allows water vapor to pass through; importantly, it can spontaneously recover cooling capacity during off hours. We selected lithium bromide as a cost-effective sorbent while avoiding crystallization. Outstandingly, the strategy can provide an effective cooling capacity (ΔTmax = 11.5°C) for ∼400 min, while the measured heat flux can reach 75 kW/m2. By employing the strategy in a real computing device, its performance is improved by 32.65% with a record-high cost effectiveness. The strategy can be useful for various applications that need intermittent thermal regulation, with few technological barriers.