Stratified Triphasic Thermocells with Boosted Thermopower Enabled by Entropy‐Concentration Dual Regulation Strategy

作者：Bin Xie, Zhi Chen, Hongcheng Li, Zhaopeng Liu, Zhaopeng Liu, Mingyu Li, Yang Huang, Guangming Chen, Zhuoxin Liu, Zhuoxin Liu · 发表于：Advanced Functional Materials · 年份：2025 · DOI：10.1002/adfm.202519934 · 被引用次数：4 · 研究领域：Advanced Thermoelectric Materials and Devices、Advanced Thermodynamics and Statistical Mechanics、Thermal properties of materials

Abstract Thermocells (TECs), a booming heat‐to‐electricity conversion technique leveraging redox reactions, face intrinsic challenges in thermopower ( S e ) enhancement, limiting their efficiency in low‐grade heat harvesting. Herein, a stratified triphasic electrolyte (STE) for TECs is presented that synergistically boosts S e via entropy‐concentration dual regulation while inherently suppressing thermal convection. By constructing immiscible neopentyl glycol (NPG)‐rich and water‐rich liquid phases interlaced with Fe(CN) 6 4− crystalline precipitates, the STE synergistically achieves solvation entropy tuning and concentration gradient amplification. The NPG‐rich phase selectively reconstructs redox ion solvation shells to elevate entropy changes, while temperature‐dependent ion solubility disparities between liquid phases generate extreme non‐equilibrium concentration ratio differences. As a result, a significantly boosted S e of 3.61 mV K −1 for Fe(CN) 6 3−/4− ‐based TECs is achieved, outperforming many state‐of‐the‐art systems reliant on singular parameter optimization. The STE‐based TEC delivers a power density of 819.8 mW m −2 at Δ T = 30 K and demonstrates stable continuous operation for hours. An integrated device combining the STE‐based P‐type units with Fe 2+/3+ N‐type counterparts is also fabricated and demonstrated to sustainably power small electronics under low thermal gradients. This work establishes a strategy to harmonize thermodynamic and kinetic optimization ...