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953 K下,在Li Cl-Li F-Li_2CO_3纯锂盐体系中,采用电化学手段(循环伏安法,计时电流法)研究了熔盐电解碳酸锂制备金属锂的电极过程,重点分析了锂的还原机制和碳酸根离子的放电行为。研究表明,金属锂在钨电极上的还原是锂离子一步得电子的可逆反应过程,在氯气析出峰前的氧化峰为碳酸锂在电场作用下分解为二氧化碳和氧化锂,氧化锂中的氧离子放电生成氧气所致,电场的作用促进了碳酸锂的分解。计时电流表明锂离子的沉积速率受扩散控制,经计算锂离子在熔盐中扩散系数为1.35×10~(-8)cm~2·s~(-1),成核过程是半球形三维瞬时成核。碳酸锂的加入比传统的以Li Cl为原料熔盐电解法制备金属锂或者合金实际分解电压低0.5 V,从而降低了电解过程电压,较少了能源消耗;使用碳酸锂作原料熔盐电解法制备金属锂不仅减少了环境污染还降低了锂的生产成本。
The electrochemical process (cyclic voltammetry, chronoamperometry) was used to study the electrodeposition of lithium metal from molten salt electrolysis of lithium carbonate at 953 K in LiCl-Li F-Li 2 CO 3 pure lithium salt system. The reduction mechanism and the discharge behavior of carbonate ions. The results show that the reduction of metallic lithium on the tungsten electrode is a one-step reversible reaction of lithium ions. The oxidation peak before the chlorine gas is decomposed into carbon dioxide and lithium oxide under the electric field and the oxygen ions in lithium oxide Discharge generated oxygen due to the role of the electric field to promote the decomposition of lithium carbonate. The chronoamperometry indicates that the deposition rate of lithium ion is controlled by diffusion. The diffusion coefficient of lithium ion in molten salt is calculated to be 1.35 × 10 -8 cm -2 · s -1. The nucleation process is hemispherical three-dimensional instantaneous Nucleation. The addition of lithium carbonate is 0.5V lower than the actual decomposition voltage of lithium metal or alloy prepared by the molten salt electrolysis using LiCl as the raw material, thereby reducing the voltage of the electrolysis process and reducing the energy consumption; and using lithium carbonate as the raw material molten salt electrolysis Preparation of lithium metal not only reduces environmental pollution but also reduces the cost of lithium production.