[exclusive]: Pppe-097

Corresponding author: maya.chen@berkeley.edu

Thermal energy storage (TES) is a cornerstone technology for enhancing the efficiency of renewable‑energy systems, yet the search for low‑cost, chemically stable, and high‑energy‑density phase‑change materials (PCMs) remains ongoing. This work introduces , a novel composite PCM comprising a polypropylene (PP) matrix reinforced with functionalized graphene nanoplatelets (f‑GNP) and encapsulated paraffin wax (C₁₈–C₃₆). The material was synthesized via melt‑mixing and hot‑pressing, followed by a two‑step micro‑encapsulation process to improve shape stability and prevent leakage. Comprehensive thermal, mechanical, and cycling tests reveal that PPPE‑097 exhibits: PPPE-097

| PCM | Latent heat (J g⁻¹) | Conductivity (W m⁻¹ K⁻¹) | Shape stability | Cycle life | |-----|----------------------|--------------------------|-----------------|------------| | Pure paraffin | 150 | 0.21 | Poor | ≤ 200 cycles | | Paraffin/SiO₂ (10 wt %) | 155 | 0.35 | Moderate | 500 cycles | | PEG/AlN (15 wt %) | 165 | 0.62 | Good | 800 cycles | | (this work) | 185 | 0.75 | Excellent | **> 1000 cycles Corresponding author: maya

| Stakeholder | Role | Value Proposition | |-------------|------|-------------------| | | Funding, standards alignment | Meets mission‑critical PPE needs; aligns with sustainability directives. | | Universities (MIT, UW‑Seattle, TU Delft) | Fundamental research, testing labs | Access to cutting‑edge polymer chemistry and sensor physics expertise. | | Industry Partners (3M, DuPont, Carbon3D) | Scale‑up, supply chain | Leverage existing polymer & AM infrastructure; co‑develop IP. | | End‑Users (Firefighters, Military, Construction) | Field validation, feedback loops | Directly benefit from lighter, smarter, recyclable gear. | | | End‑Users (Firefighters