基于固废的锂离子电池Li₂FeSiO₄/C正极材料及其电化学性能研究

Research on Li₂FeSiO₄/C Cathodes for Lithium-Ion Batteries Based on Solid Wastes and Electrochemical Performances

摘要: 随着钢铁工业的快速发展，铁尾矿排放量日益增加，大量的铁尾矿一般采用直接堆填处置，既浪费资源，又挤占耕地，需要支付土地征用费、运费和填埋费等，不仅增加钢铁企业的生产成本，还造成环境污染与安全问题。因此，铁尾矿的资源化利用亟待解决。本文以铁尾矿为原料，采用酸浸法、碱浸法、水热和固相烧结法，利用制备的FeSO₄·H₂O和含水率22.44%的白炭黑为前驱体，合成了Li₂FeSiO₄/C锂离子电池正极材料，具有较好的电化学性能。在0.1C电流密度下，经过100次充电循环，比容量保持32 mAh·g⁻¹；5C高电流密度下，比容量仍能保持20 mAh·g⁻¹。本研究充分利用铁尾矿中铁源和硅源，为铁尾矿资源高附加值利用提供一条的新思路。

Abstract: With the rapid development of the iron and steel industry, the annual discharge of iron tailings continues to soar. At present, most of these tailings are simply dumped into landfills—an approach that not only squanders valuable resources and encroaches on arable land, but also obliges steelmakers to pay land-acquisition, transportation and tipping fees, pushing up production costs while creating environmental and safety hazards. Therefore, the resource utilization of iron tailings needs to be solved urgently. In this paper, Li₂FeSiO₄/C cathode material for lithium-ion battery was synthesized from iron tailings by acid leaching, alkali leaching, hydrothermal and solid-state sintering, using FeSO₄·H₂O and silica precursor with water content of 22.44%, which has good electrochemical performance. At 0.1C, after 100 charging cycles, the specific capacity remained 32 mAh·g⁻¹; At 5C high current density, the specific capacity can still maintain 20 mAh·g⁻¹. The research content makes full use of iron source and silicon source of iron tailings, and provides a new idea for the utilization of high added value of iron tailings resources.