<p>Biochar-based form-stable phase-change materials have attracted significant interest in thermal energy storage (TES) applications in recent years because of their favorable thermal properties, enhanced structural stability, and sustainable, porous nature. This study developed a novel shape-stabilized phase-change material using paraffin (PA) as the phase-change material and peanut shell biochar (PSB) as a low-cost, ecofriendly supporting matrix. The PA/PSB composite was prepared via a direct impregnation method. The morphological structure and chemical compatibility of the composite were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The thermal properties were evaluated via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results confirmed that PA was successfully encapsulated within the porous PSB matrix through physical interactions, and a stable composite was obtained at a 1:1 mass ratio without any noticeable leakage. DSC analysis revealed that the melting and crystallization temperatures of the PA/PSB SSPCM were 331.65 K and 326.04 K, respectively, with corresponding latent heats of 78.18 J g⁻¹ and 80.42 J g⁻¹. The TGA results demonstrated that the operational temperature range of the composite was well below its decomposition temperature, indicating good thermal reliability. The prepared PA/PSB shape-stabilized phase-change material (SSPCM) has promising potential for efficient and sustainable thermal energy storage applications.</p>