锂钠合金的原位电化学制备及“锂+钠”共储特性

锂钠合金相较于单一锂或者单一钠具有更优异的性能，以钠金属为正极、锂金属为负极，以LiPF₆、NaClO₄以及锂钠混合离子电解液作为电解液，组装成纽扣电池，在梯度电流密度下进行充放电，成功实现了锂钠合金的原位电化学制备。得益于锂、钠双电化学活性离子的协同效应，不同钠含量的锂钠合金为负极的锂钠混合离子电容器均呈现良好的电化学性能。尤其是低钠量的锂钠合金负极，添加NaClO₄电解液时，活化的柠檬酸钾衍生碳（SCDC-活化）正极在1 A/g电流密度下循环300圈时仍能保持238 mA·h/g的比容量和99%的容量保持率。高钠量的锂钠合金负极，添加锂钠混合离子电解液时，SCDC-活化呈现了319 mA·h/g的比容量，并在循环1040圈时仍能保持93 mA·h/g的高比容量和98%的容量保持率。

In?situ Electrochemical Preparation of Li?Na Alloy and the Co?storage of Li+ and Na+ Ions

Compared with single lithium or sodium， lithium-sodium alloy has better performance. In-situ electrochemical preparation of lithium sodium alloy is successfully achieved in button battery which is charged and discharged under gradient current density by using sodium metal as the positive electrode， lithium metal as the negative electrode， and LiPF₆， NaClO₄ or lithium sodium mixed ion electrolyte as the electrolyte. Benefiting from the synergistic effect of lithium and sodium double electrochemically active ions， the lithium-sodium mixed ion capacitors with different lithium contents as negative electrodes show good electrochemical performance. In particular， with lithium sodium alloy with high lithium content as the negative electrode and NaClO₄ electrolyte added， Carbon derived from sodium citrate （Sodium citrate derived carbon， SCDC-activated） maintains the high specific capacity of 238 mA·h/g and the capacity retention rate of 99% at the current density of 1 A/g for 300 cycles. With the addition of lithium-sodium mixed ion electrolyte， SCDC-activated exhibits the specific capacity of 319 mA·h/g， and it can retain 93 mA·h/g and 98% capacity retention rate after 1040 cycles.