Cheaper, higher performance lithium-ion batteries from metallurgical-grade silicon
ISSUE ADDRESSED
Lithium-ion (Li-ion) batteries are ubiquitous in today's world and are one of the most significant innovations of recent decades. These batteries are the power sources for many devices and products we use every day: our smart phones, tablets, computers, electric cars... the list goes on, and the number of devices using these batteries is exploding with the times. advent of the Internet of Things (IoT). Consequently, the industry is under enormous pressure to produce higher performance and less expensive Li-ion batteries.
The performance of Li-ion batteries is limited by the material used for its anode which directly determines the energy density, capacity, life cycle (number of charge/discharge cycles) and cost. Graphite is currently the most widely used material for anodes. However, silicon (Si) has a theoretical capacity 10 times greater than that of graphite (can store 10X more lithium), allows for 40% greater energy density (energy per unit mass), and benefits from a volume per mass 35% lower than graphite for equivalent energy storage.
Currently, the widespread use of Si-based Li-ion batteries in factories is hampered by costly and multi-step production processes, such as chemical vapor deposition (CVD) and nano- surface structuring by plasma. These approaches are capital-intensive, cannot be scaled up, and use highly purified electronic-grade crystalline Si, which is expensive and involves multiple purification steps. Finally, Si tends to swell (volume expansion) and to crack after several charging and discharging cycles (when it absorbs lithium (it is "lithiumated"). This swelling causes the batteries to fail.
TECHNOLOGY
This invention solves these problems. It uses metallurgical grade Si (the second most abundant element in the earth's crust) and a simple three-step production process that is easily adaptable (potentially 10 times cheaper than CVD and plasma).
Two game-changing advances have been made. Indeed, despite the volume expansion of Si (which cannot be controlled), the inventors have reduced the probability of mechanical fracture (cracking) by a factor of 95% compared to all the other techniques currently available. Second, the silicon anode structure prevents electrochemical failures as well as loss of capacity over time. No other method is able to prevent mechanical and electrochemical failures at the same time.
The proof of concept is complete, from the production of the active material to its integration into working batteries. Several test cycles allowed to adjust the performance characteristics of the batteries. Tests have shown significant prevention of SEI growth, improved Coulomb efficiencies over 99%, and measured specific energies of up to 750 Wh/kg.
ADVANTAGES
TECHNICAL ADVANTAGES
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-Reduction of CAPEX and OPEX for the production of Liion battery anode material.
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Simple and easily scalable production method, potentially 10 times cheaper than current methods,
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Plasma-based anode material cost: ~$100/kg versus $5-30/kg for this technique.
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The resulting Si anode has the following characteristics:
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Reduces volume expansion cracking by a factor of 95% (mechanical failure),
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Reduces electrochemical failures (doubling the number of cycles),
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Reduces capacity loss over time, and therefore lifetime, by a factor of 3 to 5.
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The use of silicon as an active material offers the following advantages:
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A theoretical capacity 10 times greater than that of graphite (can store 10 times more lithium),
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An energy density (energy per unit mass) 40% higher than that of graphite,
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35% less volume/weight than graphite for equivalent energy storage.
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Increasing the life cycle of Li-ion batteries by controlling the volume expansion and formation of the semiconductor electrolyte (SEI) interphase, particularly relevant for electric vehicles.
COMMERCIAL BENEFITS
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Possibility of increasing the capacity of Li-ion batteries while reducing the cost.
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Cheaper anode materials, larger capacity batteries, lower production costs.
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Anode cost reduced by a factor of 10+ while benefiting from the very interesting properties of Si, namely increased capacity.
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Abundant raw material - Metallurgical Si - 100X cheaper than electronic Si
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(~$1.20/kWh versus >$100/KWh) - (Source: Tesla: 2020 Annual Shareholder Meeting and Battery Day).
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The future of several advanced technologies is linked to the evolution of Li-ion batteries.
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The Li-ion battery market is estimated at $38.6 billion in 2020, to reach $116.6 billion in 2030, with a CAGR of 12.3%, a tripling in 10 years.
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90% of this market is compatible with the batteries of this invention.
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Li-ion Battery Anode Market is estimated to be valued at USD 8.5 Billion in 2021 to reach USD 20.9 Billion in 2026 with a CAGR of 19.9%.
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Targeted Application Market Size and CAGR
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Electric vehicles - US$162 billion to US$803 billion (2019-2027), CAGR of 22.6%.
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Internet of Things (IoT) - US$10.6B to $561B (2017-2022), CAGR 26.9%.
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Smart Grids - US$67 billion to US$169 billion (2017-2025), CAGR of 12.4%.
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No other solution offers the game-changing advantages of this invention.
APPLICATIONS
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Lithium ion (Li-on) batteries.
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Target applications of batteries:
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Electric vehicles
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Internet of Things (IoT)
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Intelligent networks (grids)
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INTELLECTUAL PROPERTY STATUS
TECHNOLOGY MATURITY
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TRL 4-5 with microelectronics grade silicon
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TRL 3-4 with metallurgical grade silicon.
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Proof of concept completed; several batteries built, characterized and optimized with this new active material in mesoporous Si for the anode, in several test cycles.
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Developments are continuing along these lines:
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Characterization and testing of silicon-based anode materials in Li-ion batteries.
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INTELLECTUAL PROPERTY
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Patent application filed.