Scalable and universal synthesis of hierarchical organic/carbon composites towards practical organic batteries

Abstract

Organic electrode materials with renewability, environmental benignity, and structural tunability have attracted increasing attention for lithium-ion batteries, but their practical application is hindered by low mass loadings (< 2 mg cm⁻²) and inadequate areal capacities (< 0.5 mAh cm⁻²), primarily due to low electronic conductivity and sluggish ion diffusion. Here, we address these limitations by introducing a scalable spray-drying method to synthesize hierarchical organic/carbon composites. By using lithium terephthalate (Li₂TP), carbon nanotubes (CNTs), and polyvinylpyrrolidone as precursors, we fabricate Li₂TP-H, a composite featuring Li₂TP nanoparticles (∼20 nm) assembled into microspheres with 3D CNTs networks. This hierarchical design ensures efficient ion and electron transport, yielding a high capacity retention of 91.6% (from 298 to 273 mAh g⁻¹) when increasing mass loading from 2 to 43 mg cm⁻². The resulting areal capacity of 11.7 mAh cm⁻² ranks among the highest reported for organic electrodes. Moreover, the methodology is extendable to other carboxylate-based compounds, with all derivatives exhibiting enhanced performance under a high-mass-loading of 10 mg cm⁻². This work provides a new paradigm for developing high-areal-capacity organic electrodes, representing a pivotal step toward commercializing organic battery technologies.