Glass can be completely recycled with no quality loss. It is made from sand and other supplements (soda ash, limestone, etc.), meaning the material must be heated to 1400-1600C, which requires a huge source of energy.
According to the U.S. Energy Information Administration, natural gas is the most common heat source (73 percent), followed by electrical energy (24 percent). Yet despite the upfront costs, recycling processes generally save energy by reducing emissions and raw material consumption.
The most common batteries, lithium-ion, have a wide range applications, from small electronic devices to electric vehicles. These batteries are usually made of lithium cathodes and graphite anodes. The graphite anode works well because of its resistance to expansion during the charging-discharging process.
During the charging process, the battery is heated and gasses are released inside during electrolyte decomposition, which inflates the battery, potentially causing safety and battery performance issues. Most electronic devices are not designed to allow large battery volume expansion (usually the battery volume expansion tolerance is, at most, five percent).
The disadvantage of carbon as an anode is its low energy density (370 mAh/g), which makes it less than ideal for storage.
The increasing energy requirements of electronic devices and electrical vehicles imposes demands for higher capacities and energy densities in the batteries, which is why silicon is becoming a popular material for battery researchers. It has very high capacity (4200 mAh/g), basically, the highest energy density value compared to all other materials.
Battery researchers are focusing on silicon because it has great potential for designing a super battery. Moreover, it’s inexpensive and easily available, obtainable in a green way by recycling glass garbage.
Unfortunately, silicon is not a perfect magic material; it has its own disadvantages.
During the battery charging process, silicon reacts with lithium creating the composite SiLix. The result of this process is a significant structural change where the Si expands by 300-400 percent and causes Li-ion batteries to swell. This causes the mechanical stress and silicon structure pulverization, which are associated with electrolyte interface. This process usually leads to battery failure, and is the reason silicon batteries do not have long lifecycles.
Silicon’s huge energy density value could lead to a new generation of high capacity batteries, but this means solving the material’s expansion during the charging process is critically important. Extending the lifecycle of this battery type is the main challenge for the researchers.
One of the most recent battery designs utilizes a nano-architecture silicon diode. In this design, silicon nanowires (at a length of a few microns) are mixed with graphene and carbon nanotubes. Test results of this solution show that there is a less contact between the lithium and electrode, result in higher stability which, in turn, prevented the expansion.
The second possible solution is to use a composite of silicon and metal. Metal does not react with Lithium and makes a matrix which decreases the volume expansion. Using the new binders—such as alginic acid (AA), polyamide-imide (PAI) and polyimide (PI)...)—which can provide more volume expansion, is a potential solution.
Still, the best and fastest short-term solution is a combination of silicon material which has great energy density with graphitic carbon, which has good physical and chemical performance. This solution does not offer as high a capacity as silicon alone, but has a significantly longer life cycle than pure silicon anode batteries.