High-Performance Mg–Al–Bi Alloy Anode for Seawater Batteries and Related Mechanisms

Changqing Wu,Wei Wang,Xu Meng

doi:10.3390/pr8111362

Abstract

Bi, a group 15 element, was added to magnesium alloys and applied to seawater batteries in marine operating machinery to improve the electrochemical performance and corrosion resistance of the battery. The electrochemical properties of as-cast pure Mg, Mg–8Al, and Mg–8Al–xBi alloy anodes in 3.5% NaCl solution were researched. Electrochemical impedance spectroscopy and an immersion test in 3.5% NaCl solution show that the Mg–8%Al–0.4%Bi alloy provides better corrosion resistance than Mg and the Mg–8Al alloy. The galvanostatic discharge results show that the Mg–8%Al–0.4%Bi alloy revealed better electrochemical properties and utilization efficiency in 3.5% NaCl solution. The Mg17Al12 and BiOCl phases formed during the discharge process of the Mg–8%Al–0.4%Bi alloy play an important role in improving the electrochemical performance and utilization efficiency of the alloy.

Highlights

Due to environmental pollution and energy issues, ocean research has attracted widespread attention and has become a hot topic; ocean research requires solutions to resolve its energy needs [1,2]
This battery system applies active metal as the battery anode; AgCl, CuCl, Cu2 I2, and PbCl2 as the battery cathode; and natural seawater is used as the electrolyte, which is different from the lithium-ion battery system that normally uses porous carbon as the anode [3] and metal oxide (e.g., LiMn2O4) as the cathode [4]
The relatively stable stable open circuit potential indicates electrochemical state electrode surface is relatively open circuit potential indicates thatthat thethe electrochemical state on on thethe electrode surface is relatively stable

Summary

Introduction

Due to environmental pollution and energy issues, ocean research has attracted widespread attention and has become a hot topic; ocean research requires solutions to resolve its energy needs [1,2]. A seawater-activated battery was invented in the 1940s to solve the requirements of ocean exploration and research. This battery system applies active metal (e.g., magnesium, aluminum) as the battery anode; AgCl, CuCl, Cu2 I2 , and PbCl2 as the battery cathode; and natural seawater is used as the electrolyte, which is different from the lithium-ion battery system that normally uses porous carbon (e.g., graphite) as the anode [3] and metal oxide (e.g., LiMn2O4) as the cathode [4]. The electrolyte is seawater, so extra electrolytes and storage devices do not need to be found For this reason, the weight of the appliance can be greatly reduced. In order to obtain high-performance seawater batteries, high-performance anode materials have become the focus of development [13]

Methods

Results

Discussion

Conclusion