China turns liquor waste into high-performance starting material for anode for sodium-ion batteries with 91,9% retention after 100 cycles – Interesting Engineering
Sodium-ion batteries are safer and cheaper than lithium-ion batteries but need to improve their performance to be commercially deployed.
Researchers at the University of Electronic Science and Technology of China (UESTC) have turned the by-product of the popular Chinese liquor baijiu into a high-performance starting material for anode for sodium-ion batteries, the next-generation energy storage solution. The team has been granted patents for their approach and is now looking to scale up the technology, a media report said.
Baijiu, or Shaojiu, is a popular Chinese liquor that is colorless or clear with a distinct flavor profile. Made from wheat grain or rice, the alcohol content in this drink varies from 35 to even 60 percent.
Over the years, it has become the quintessential drink when visiting China. Still, a team led by Liu Xingquan, a professor at UESTC, looked at the sediment left over after the distillation of the liquor as a starting material for improving the energy storage of sodium-ion batteries.
Improving sodium-ion batteries
While the onus of the global energy transition from fossil fuels to renewable sources has fallen on lithium-ion batteries, scientists are looking for ways to overcome their higher costs and safety concerns.
Sodium-ion batteries offer a much cheaper and safer alternative as energy storage solutions. However, since sodium ions are much larger than lithium ones, the anode or the positive electrode needs to have larger internal pores than the anode used in lithium-ion batteries.
While lithium-ion batteries use graphene for anodes, sodium-ion batteries have been teamed up with hard carbon for anodes. However, the material suffers from low coulombic or charge efficiency, severely limiting its performance. Additionally, the frequent insertion and removal of ions can lead to a micropore collapse in hard carbon, which reduces the battery’s energy density and life cycle.
Baijiu by-product as starting material
Liu’s team was looking for an alternate carbon source when they turned to Wuliangye, a Sichuan-based manufacturer of baijiu. As one of the largest drink manufacturers, Wualiangye generates a significant amount of sediment during manufacturing, which is otherwise used as feed or fertilizers.
UESTC researchers sourced the sediment and treated it by washing, drying, acid-leaching, and pre-carbonising it. To remove the silica content, they treated it with sodium hydroxide, activated the hard carbon at high temperatures, and mixed it with ethyl orthosilicate, the South China Morning Post reported.
The final mixture was then treated with ultrasound before another treatment at high temperatures to form silicon-doped hard carbon, which the team called HC-1100Si-1.
To verify the material’s performance, the team assembled a sodium-ion battery with HC-1100Si-1 at its anode and sodium manganese oxide at the cathode. The researchers found that the battery had a reversible capacity of 281.5 mAh/g at 1C and retained 91.9 percent capacity even after 100 cycles.
While this is below the standard expected capacity of commercially deployed batteries, the researchers are looking to deploy these batteries for applications that require frequent charging and discharging instead of long-term performance on a single charge.
Since current approaches to sourcing hard carbon use tar as a starting material, using baijiu sediment is cost-effective and environment-friendly. The research team is working to scale up the production of hard carbon to a kilogram level in the near future.
The research findings were published in ACS Applied Materials & Interfaces.
READ the latest Batteries News shaping the battery market
China turns liquor waste into high-performance starting material for anode for sodium-ion batteries with 91,9% retention after 100 cycles – Interesting Engineering, source
