Huiyue Wang, Ling Chen, Xueying Wen, Linhui Fu, Wenqian Xing, Guixin Hu, Qianyu Wei, Ran Niu, Haolan Xu*, Jiang Gong*

Spongiatia-inspired carbon nanotube microspheres encapsulating phase change materials for all-day freshwater-electricity co-generation

Journal of Materials Science & Technology (2026) Accept. (IF2026 = 16.8)

Integrating interfacial solar steam generation with phase change materials (PCM) has emerged as an efficient approach for all-day solar-driven freshwater-electricity co-generation. However, building those multi-functional evaporators requires complex materials design and leakage-free PCM encapsulation. Herein, we develop a simple, one-step pore engineering strategy to synthesize carbon nanotube microspheres (CNM) with rich nano-/micro-scale pores using waste polypropylene as raw materials and subsequently construct persistent PCM@CNM composite-based multi-functional evaporators. The synergistic effect of multi-level pores significantly promotes PCM encapsulation, realizing an extremely low PCM leakage of <0.4%. The high thermal conductivity of PCM@CNM (0.547 W m^-1 K^-1) enables fast thermal energy transfer and utilization for improving water evaporation and thermoelectricity generation. Under one Sun irradiation, the evaporator delivers an evaporation rate of 2.7 kg m^-2 h^-1 and a voltage output of 217 mV, surpassing the state-of-the-art PCM-containing evaporators. During outdoor tests, a voltage output of 3 V is achieved, which can charge a mobile phone. Technoeconomic analysis results indicate that the cost-effectiveness of PCM@CNM stands at 209.30 g h^-1 $^-1. This work offers a cost-effective, sustainable platform to produce multi-functional evaporators for all-day freshwater-electricity co-generation.

Keywords: Solar steam generation; Freshwater-electricity co-generation; Phase change energy storage; Carbon nanotube microsphere; Chemical recycling