Chinese researchers have proposed using recycled silicon from discarded solar cells to build anodes. They combined recycled waste silicon powder with graphite, creating a composite material that is claimed to have remarkable electrochemical performance.
“The purpose of our work was to propose a simple and efficient recycling method that aims to realize value-added reuse of silicon materials in end-of-life photovoltaic modules,” said Shaoyuan Li, lead author of the study. pv magazine. “According to current traditional engineering methods such as acid and alkali leaching, one ton of end-of-life solar modules can recover 40 kg of silicon material, which can generate a net income of $104.9. Combining recycled silicon material with graphite using a simple ball milling process to produce a silicon-carbon composite anode can generate $1,883 in revenue.
In the study “High-performance silicon carbon anodes based on a value-added recycling strategy for end-of-life PV modules published Energythe researchers explained that the waste silicon powder (W-Si) needed for the battery’s anodes was obtained by grinding pieces of solar cells with a vibrating mill.
The cells had previously been mechanically detached from the modules and then cut into 6 mm x 6 mm pieces. These fragments were then soaked in a toluene solution for 24 hours to dissolve them ethylene vinyl acetate (EVA) encapsulant. “To further remove EVA, the EVA-wrapped cell fragments were placed in a tube oven for pyrolysis at 550 C for 2 h under an argon atmosphere,” they said. “Deionized water and ethanol were used for ultrasonic cleaning several times to obtain solar cell fragments.”
Using these fragments, the research team developed waste silicon powder by combining recycled silicon with graphite using a simple ball milling process. The resulting composite material, called (email protected), showed remarkable electrochemical performance.
“Its original discharge capacity was up to 1,770 mA hg-1maintained a good specific capacity of 913 mA hg-1 After 200 cycles at a current density of 500 mA g-1and the average Coulombic efficiency reached 98.99%, which was only 0.24% capacity loss,” Li explained, noting that the use of graphite created a buffer space for silicon volume expansion, improving the material’s cyclic stability. “The graphite had a good contact with the silicon particles, and the introduction of graphite greatly improved the electrical conductivity of the silicon material.”
Going forward, the researchers said more work is needed to build a full and efficient value-added recycling industry for end-of-life solar modules, highlighting the current difficulties in establishing viable businesses in this sector without public support. “The recycling of specialized solar modules has a certain economic viability, but it is not economical enough to sustain the smooth operation of the company,” they stated.