Their important research, published in Nature Sustainability on July 16, paves the way for more sustainable, cost-effective, and high-energy-density batteries, potentially revolutionizing energy storage systems for electric vehicles and renewable energy uses.
Silicon anodes are known for significantly increasing the energy density of lithium-ion batteries compared to traditional graphite anodes but face challenges due to substantial volume expansion during charge-discharge cycles. This expansion can lead to mechanical fractures and degrade battery performance.
To address these issues, the research team, led by Prof. CUI Guanglei, developed micro-sized silicon (um-Si) particles from photovoltaic waste as a promising alternative.
When combined with a specially formulated ether-based electrolyte, these um-Si anodes show exceptional electrochemical stability, maintaining an average coulombic efficiency of 99.94% and retaining 83.13% of their initial capacity after 200 cycles.
"This work not only suggests a more sustainable supply source for silicon particles but also addresses the major challenges facing micro-sized silicon anode materials," said Dr. LIU Tao, first author of the study.
The success of the anodes is attributed to their unique solid-electrolyte interphase (SEI) chemistry, stemming from the team's innovative electrolyte composition of 3 M LiPF6 dissolved in a 1:3 volume ratio of 1,3-dioxane and 1,2-diethoxyethane. This formulation promotes the development of a dual-layer SEI that is both flexible and robust, holding together fractured silicon particles while enhancing ionic conduction and minimizing side reactions.
The NCM811||um-Si pouch cells with the new anode and electrolyte combination survived 80 cycles and delivered an impressive energy density of 340.7 Wh kg-1 under harsh conditions. This performance marks a significant improvement over conventional lithium-ion batteries, which are nearing their energy density limits.
Dr. DONG Tiantian, another co-first author of the study, highlighted the environmental benefits: "The sustainable sourcing of silicon from discarded solar panels mitigates both the economic and environmental impacts of photovoltaic waste. Converting waste into valuable battery components significantly reduces the cost of lithium-ion batteries and increases their accessibility."
"By using recycled materials and advanced chemical engineering, we have demonstrated that high-performance and environmentally sustainable lithium-ion batteries are not only possible, but also within reach," said Prof. CUI, who is optimistic that this research will lead to the development of next-generation batteries capable of powering everything from electric vehicles to grid-scale energy storage.
This major approach exemplifies how innovative recycling and meticulous materials science can converge to solve some of the most pressing challenges in energy technology today.
Research Report:Recycled micro-sized silicon anode for high-voltage lithium-ion batteries
