氯化镍阳离子添加剂对酸性水系锡负极电化学性能的研究

Study on the Effect of Nickel Chloride Cationic Additive on the Electrochemical Performance of Tin Anode in Acidic Aqueous System

摘要: 水系锡基电池因安全性高、成本低廉而备受关注，但锡负极在沉积/溶解过程中易出现“死锡”积累、枝晶生长及析氢副反应等问题，严重制约其循环寿命。本文以甲基磺酸锡(Sn(CH₃SO₃)₂)为锡源、甲基磺酸(CH₃SO₃H)为支持电解质，引入氯化镍(NiCl₂)作为阳离子型添加剂，系统研究其对锡沉积/溶解行为的影响。实验结果表明，Ni²⁺通过静电吸附在锡电极表面形成屏蔽层，能有效降低成核过电位(降低约5 mV)，促进锡均匀致密沉积。在10 mA cm⁻²、1 mAh cm⁻²条件下，含0.1 mol L⁻¹ NiCl₂的电解液可使Cu//Sn不对称电池稳定循环超过2800次，平均库伦效率达99.92%。以四氯苯醌(TCBQ)为正极的全电池在10 C倍率下循环3000次后容量保持率为71%。本工作首次将阳离子静电屏蔽策略应用于水系锡负极，为提升锡基电池的循环稳定性提供了简便有效的电解液设计思路。

Abstract: Aqueous tin-based batteries have attracted considerable attention due to their high safety and low cost. However, the Sn anode suffers from “dead Sn” accumulation, dendrite growth, and hydrogen evolution reaction during the plating/stripping process, which severely limits its cycle life. Herein, nickel chloride (NiCl₂) is introduced as a cationic additive into a tin methanesulfonate (Sn(CH₃SO₃)₂) electrolyte. The results show that Ni²⁺ forms an electrostatic shielding layer on the Sn electrode surface via electrostatic adsorption. This shielding layer effectively reduces the nucleation overpotential (by approximately 5 mV) and promotes uniform and compact Sn deposition. In the Cu//Sn asymmetric cell, the NiCl₂-containing electrolyte achieves over 2800 stable cycles at 10 mA cm⁻² and 1 mAh cm⁻², with an average Coulombic efficiency of 99.92%. In the TCBQ//Sn full cell, a capacity retention of 71% is maintained after 3000 cycles at 10 C rate. This work demonstrates the first application of cationic electrostatic shielding to aqueous Sn anodes, providing a simple and effective electrolyte design strategy for high-performance Sn-based batteries.