{'fraction_non_alphanumeric': 0.050788091068301226, 'fraction_numerical': 0.01138353765323993, 'mean_word_length': 5.421348314606742, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Low-Cost Rapid Template-Free Synthesis of Nanoscale Zinc Spinels for Energy Storage and Electrocatalytic Applications

Spinels form an interesting class of compounds, finding applications in metal-ion batteries and as catalysts for metal–air batteries and fuel cells. Here, we report a fast, template-free solution combustion method to synthesize nanoscale zinc spinels for applications as cathodes in low-cost aqueous zinc-ion batteries and oxygen reduction reaction (ORR) catalysts. It leads to the formation of phase-pure spinels with near spherical nanoscale morphology. Three spinels—ZnCo2O4 (ZCO), ZnMn2O4 (ZMO), and ZnMnCoO4 (ZMCO)—were investigated. ZMO and, for the first time, ZMCO were observed to show reversible Zn (de)insertion involving Mn4+/Mn3+ redox couple with a first discharge capacity of 109.4 mAh/g (i.e., >99% of theoretical capacity). Further, these Zn-based spinels showed appreciable oxygen reduction reaction (ORR) electrocatalytic activity. The ORR activity in alkaline solution was characterized by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) using a rotating disk electrode (RDE) and was obser...