Enhanced reversible capability of a macroporous ZnMn2O4/C microsphere anode with a water-soluble binder for long-life and high-rate lithium-ion storage

Abstract

Among the many transition metal oxides, ZnMn₂O₄ provides relatively high theoretical capacity, low cost, low toxicity, and environmental friendliness for high-performance lithium-ion batteries. However, ZnMn₂O₄ suffers from limited cycle life, originating from poor electronic conductivity and huge volume change. In this work, ZnMn₂O₄/C consisting of many carbon layer-coated tiny nanoparticles, forming rough and macroporous microspheres, and microsphere anodes, with water-soluble sodium carboxymethyl cellulose or non-water-soluble poly(vinylidene fluoride), are characterized by electrochemical testing. As a result, the cell with water-soluble sodium carboxymethyl cellulose was shown to exhibit a high reversible capacity of 1249 mA h g⁻¹ after 100 cycles at a low current density of 200 mA g⁻¹. Even at a high current density of 500 mA g⁻¹, it still retains a reversible capacity of 820 mA h g⁻¹ after 500 cycles with a high coulombic efficiency, thus indicating its long life and high rate.