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Deriving battery grade materials from natural sources is a key element to establishing sustainable energy storage technologies. In this work, we present the use of avocado peels as a sustainable source for conversion into hard carbon-based anodes for sodium ion batteries. The avocado peels are simply washed and dried then proceeded to a high temperature conversion step. Materials characterization reveals conversion of the avocado peels in high purity, highly porous hard carbon powders. When prepared as anode materials they show to the capability to reversibly store and release sodium ions. The hard carbon-based electrodes exhibit excellent cycling performance, namely, a reversible capacity of 352.55 mAh g⁻¹at 0.05 A g⁻¹, rate capability up to 86 mAh g⁻¹at 3500 mA g⁻¹, capacity retention of >90%, and 99.9% coulombic efficiencies after 500 cycles. Cyclic voltammetry studies indicated that the storage process was diffusion-limited, with diffusion coefficient of 8.62 × 10⁻⁸cm²s⁻¹. This study demonstrates avocado derived hard carbon as a sustainable source that can provide excellent electrochemical and battery performance as anodes in sodium ion batteries.

 

We report observations of photopolymerization driven phase-separation in a mixture of a photo-reactive monomer and inorganic nanoparticles. The mixture is irradiated with visible light possessing a periodic intensity profile that elicits photopolymerization along the depth of the mixture, establishing a competition between photo-crosslinking and thermodynamically favorable phase-separating behavior inherent to the system. In situ Raman spectroscopy was used to monitor the polymerization reaction and morphology evolution, and reveals a key correlation between irradiation intensity and composite morphology extending the entire depth of the mixture, i.e. unhindered phase-separation at low irradiation intensity and arrested phase-separation at high irradiation intensity. 3D Raman volume mapping and energy dispersive X-ray mapping confirm that the intensity-dependent irradiation process dictates the extent of phase separation, enabling single-parameter control over phase evolution and subsequent composite morphology. These observations can potentially enable a single-step route to develop polymer–inorganic composite materials with tunable morphologies.