It has the characteristics of high efficiency, safety and abundant resources.
Magnesium batteries are moving from laboratory to application
◎Our reporter Yong Li
At present, my country is at the leading level in the research and processing of magnesium metal. The National Magnesium Alloy Engineering Technology Research Center of Chongqing University has the world's largest magnesium battery research team and magnesium solid-state hydrogen storage team, and has developed a variety of magnesium ion batteries and A new type of hydrogen storage material with a hydrogen storage density of up to 6.1wt% and high safety.
With the development of new energy vehicles, mobile phones, computers and other technologies, batteries have become a necessity in our lives.
However, as the current main power source battery, lithium battery has problems such as shortage of resources, high cost, serious environmental pollution, and poor safety.
As an important raw material for lithium batteries, the price of lithium carbonate has not yet seen the ceiling.
According to reports, on November 7, the average spot price of domestic battery-grade lithium carbonate in Wuxi electronic disk was 615,000 yuan / ton, and the highest price was 617,000 yuan / ton.
To this end, the industry has been looking for other technical routes.
In the "post-lithium battery" era, which kind of battery can replace lithium battery?
Recently, the "Magnesium Ion Battery" project jointly completed by the National Magnesium Alloy Materials Engineering Technology Research Center of Chongqing University, Guangdong National Research Institute, Guangdong Academy of Sciences and other units won the 2022 International "Magnesium Future Technology Award".
This has added new possibilities for magnesium-ion batteries to replace lithium batteries, and also inspired new expectations in the industry.
Magnesium battery may become the replacement of lithium battery
It is understood that the global lithium resources are about 39.5 million tons, while the lithium reserves with commercial mining value are only 13.519 million tons.
If the demand for lithium batteries explodes, it is expected that the global lithium resources will be exhausted in less than 17 years, which is one of the reasons for the high cost of lithium batteries.
Its energy storage cost is roughly 0.6-0.9 yuan/kWh, which is still far from the target cost of 0.3-0.4 yuan/kWh for large-scale applications.
At the same time, the higher the energy density, the worse the safety is, which is a difficult problem for lithium batteries to solve at present.
In addition, some lithium battery systems have serious environmental pollution in the process of production and use.
The development of a new generation of high-efficiency, environmentally friendly and safe batteries has become the focus of the development of the global battery industry.
Hydrogen fuel cells, sulfur-based all-solid-state batteries, sodium-ion batteries, magnesium-ion batteries... Scientists are constantly exploring alternatives to lithium batteries.
"Magnesium batteries have the characteristics of high efficiency, safety, and abundant resources. Once technological breakthroughs are made, it will become a subversive revolution in the battery industry, and the market can reach more than one trillion yuan." Academician of the Chinese Academy of Engineering, director of the National Engineering Technology Research Center for Magnesium Alloy Materials, Chongqing University professor Pan Fusheng said in an exclusive interview with a reporter from Science and Technology Daily that compared with lithium, magnesium-based energy storage materials have the advantages of abundant resource reserves, low cost and high safety performance. High energy density battery material.
Pan Fusheng further explained that magnesium materials have relatively stable chemical properties, and their melting point is as high as 651 degrees Celsius. Magnesium batteries are relatively safe, with high melting and boiling points, and are not prone to magnesium dendrites and explosions.
Magnesium is the metal material with the highest hydrogen storage density among all solid-state hydrogen storage materials, which can reach 1,000 times the density of gaseous hydrogen and 1.5 times that of liquid hydrogen.
At the same time, because magnesium hydrogen storage is at normal temperature and pressure, the safety is much higher than that of high-pressure gaseous and liquid hydrogen storage.
The volume theoretical energy density of magnesium batteries is comparable to that of lithium batteries.
my country is rich in magnesium resources, accounting for 70% of the world's, and the cost of magnesium is only 1/25-1/50 of that of lithium.
In terms of environmental protection, after 2015, magnesium in the process of smelting, manufacturing, application and recycling, the pollution emissions are less than aluminum alloy, has become a truly advanced green material.
It is understood that magnesium batteries have been identified as research projects by the European Union; the US Department of Energy has also begun to arrange projects to support a group of well-known research units to participate in research; the Japanese battery industry believes that magnesium batteries may become a subversive of lithium batteries.
Overcome difficulties from the three major components of the battery
There are still many technical and material problems that need to be overcome in order for magnesium batteries to move from the laboratory to practical applications.
"The battery is mainly composed of three parts: positive electrode, negative electrode and electrolyte. Our research mainly starts from these three aspects." Huang Guangsheng, a professor at the School of Materials Science and Engineering of Chongqing University, introduced that in terms of positive electrode materials, they have developed high-capacity batteries. The composite sulfur material has a high specific capacity of 1200 milliampere-hours/gram (mAh/g); the high-rate porous copper sulfide nanospheres, the specific capacity can reach 250mAh/g; the long-life high-voltage manganese-based Prussian blue material can achieve 3 Volt (V) voltage, cycle life of 10,000 times.
In terms of anode materials, they have studied more than a dozen magnesium alloy anodes, which have the advantages of not easy passivation and a specific capacity greater than 500mAh/g; the artificial interface layer protects the metal magnesium anode, and the overpotential is only 50 millivolts (mV).
In terms of electrolyte, in 2020 they developed a new low-cost all-inorganic salt electrolyte MLCH, which has high conductivity and stability; at the same time, the team also developed a high-voltage, low-cost electrolyte The non-nucleophilic boron-based electrolyte has successfully achieved batch trial production of key materials such as positive electrode and electrolyte, and developed an ampere-hour magnesium soft pack battery.
The important technological progress of the three key components of the battery has laid the foundation for the magnesium battery to go out of the laboratory and into the application.
In the laboratory of the Magnesium Center of Chongqing University, the reporter saw that several magnesium batteries were undergoing charge and discharge tests.
Huang Guangsheng introduced that the test results show that the energy density of magnesium-Prussian blue batteries, magnesium-sulfur batteries, magnesium-copper sulfide batteries, and magnesium-vanadium dioxide batteries developed by them has been higher than that of lithium iron phosphate batteries, especially magnesium-sulfur batteries. It reached 785 watt-hours/kilogram (Wh/kg), while the graphite-lithium iron phosphate battery was only 160Wh/kg.
"At present, we already have the manufacturing technology of a series of batteries such as magnesium-air batteries, seawater-activated batteries, and magnesium dry batteries." Huang Guangsheng introduced that magnesium-air batteries are a type of primary magnesium fuel cells. The cathode uses air and is oxidized by cathode and anode. Reduction reaction discharge is a clean, safe and efficient new energy battery, its energy density is more than 20 times that of lead-acid batteries.
At present, they have cooperated with enterprises to start mass production.
The magnesium seawater activated battery is a device that directly uses seawater to convert the chemical energy of metal magnesium into electrical energy. It uses magnesium as the negative electrode material and seawater as the electrolyte. Its most prominent feature is that it does not need to carry an additional electrolyte and has high energy density. It has the advantages of good safety and full-sea deep work, and has a good application prospect in the field of marine equipment such as deep-sea landers and deep-sea in-situ experimental stations.
Create a new energy storage technology innovation platform
"In the research and development of magnesium hydrogen storage and magnesium batteries, my country has a significant technical foundation and advantages." Pan Fusheng pointed out that my country is already at the leading level in the research and processing of magnesium metal, and the National Magnesium Alloy Engineering Technology Research Center of Chongqing University has the world's The largest magnesium battery research team and magnesium solid-state hydrogen storage team have developed a variety of magnesium-ion batteries and new hydrogen storage materials with a hydrogen storage density of up to 6.1wt% and high safety, and their main indicators are at the world's leading level.
From 2018 to 2019, Chongqing University and Chongqing Science and Technology Bureau jointly invested more than 20 million yuan to support research on magnesium energy storage materials.
In 2020, Guangdong Guoyan Science and Technology Research Center Co., Ltd., Chongqing University, Guangdong Academy of Sciences, etc. jointly launched a magnesium energy storage material research and development project with a total investment of 500 million yuan, and established a magnesium-based energy storage research and development center in the Guangdong-Hong Kong-Macao Greater Bay Area. And industrial application demonstration base, magnesium batteries and magnesium-based solid-state hydrogen storage/transportation are about to enter trial production and demonstration applications.
In May this year, Chongqing University and Chongqing Liangjiang New Area jointly established the Chongqing New Energy Storage Materials and Equipment Research Institute (hereinafter referred to as the Research Institute).
The research institute aims at the national energy strategy and cutting-edge technologies of energy transformation, focuses on the transformation of scientific and technological achievements, and aims to build the world's largest research institute of new energy storage materials and equipment.
It is understood that Qingyang County, Anhui has rich magnesium ore resources, with an annual output of raw magnesium up to 300,000 tons, and has a good foundation for the development and preparation of magnesium-based materials.
The institute plans to carry out a series of magnesium battery demonstration projects in the "Magnesium Energy Town" to develop battery cars, street lamps, tourist vehicles and distributed energy storage systems.
The Chongqing Guangyang Island project plans to carry out a number of magnesium hydrogen storage and magnesium battery demonstration projects on Guangyang Island, including battery cars, magnesium battery street lamps, solid-state hydrogen storage and hydrogenation stations, and hydrogen energy vehicles.
"This year, we will start the pilot test of magnesium power batteries, and cooperate with enterprises to first use magnesium batteries for electric bicycles." Pan Fusheng revealed that the performance of magnesium batteries has reached the level of lithium iron phosphate batteries, which means that magnesium batteries have The possibility of commercial use as a power battery.
Of course, further research is needed to replace lithium batteries. In this regard, they have also launched a global talent recruitment campaign by the Chongqing Institute of New Energy Storage Materials and Equipment to jointly build an energy storage technology innovation platform to help the development of my country's new energy storage field.