Investigation and Optimization of Electrochemical Lithium Storage in Natural Stibnite

Abstract

Natural mineral materials with high specific capacity have attracted much attention in lithium-ion battery materials. Stibnite is an important mineral material, its main composition is Sb₂S₃, with a two-dimensional layered structure, high grade, easy to mine, and so on. In this study, natural antimony was used as electrode material to construct a lithium-ion secondary battery. Although it can provide a high initial specific capacity of 985 mAh g⁻¹, cycling stability is poor and needs to be improved. The main mechanism of capacity degradation is determined by a comprehensive analysis of ex situ XRD, SEM, and electrochemical impedance spectroscopy. By utilizing the three-dimensional network structure of sodium carboxymethyl cellulose, the volume expansion induced by alloying is effectively suppressed in the reduced charge–discharge range. In addition, antimony electrodes enhance conductivity by adding the optimal proportion of carbon materials. The results showed that sodium carboxymethyl cellulose was selected as binder and charged and discharged in the range of 0.6–2.5 V with 7:1:4 carbon addition, the electrode has a reversible specific capacity of 429 mAh g⁻¹ at 0.1 A g⁻¹. By using antimony sulfide material without chemical synthesis, the capacity retention rate was increased from 1% to 40%, which greatly reduced the material processing cost.