EnerG2 nano-structured hard carbon boosts Li-ion anode capacity by >50% compared to standard graphite
|A chart from EnerG2’s 2012 DOE Merit Review presentation shows different pore profiles for different energy storage applications. Click to enlarge.|
EnerG2, a manufacturer of advanced carbons for next-generation energy storage (earlier post), has begun production of nano-structured hard carbon for Li-ion battery anodes that it says can boost anode capacity by more than 50% over standard graphite.
Engineering surface area, pore size distribution, and total pore volume can deliver carbon material with a broad range of surface properties. These properties can be tailored and modified for adaptation to the specific requirements of a given energy storage application.
The [nano-structured hard] carbon is able to store more than standard graphite (which is what the 50% is based on) because it has a disorganized amorphous structure. Graphite is fundamentally limited to a crystal structure that sets the lithium carbon stoichiometry at one lithium for every six carbon atoms. Hard carbon is not limited in this way because of the disorganized morphology and so it can store a higher number of lithium atoms for every carbon atom. EnerG2 has used the Carbon Technology Platform to molecularly engineer the polymer precursor to result in the desired carbon structure that has both high capacity and high first cycle efficiency.— Dr. Aaron Feaver, CTO and Co-Founder of EnerG2
Using its process, EnerG2 can can tune the nano-composite for various performance variables—e.g. capacity, power, cycle life, Dr. Feaver noted. The company is not yet announcing specific performance variables and nano-composite formulations, but asserts it is making the highest performing materials yet developed.
We have broken through a critical performance barrier. Li-ion batteries are clearly dominating the imagination and innovation of the energy storage industry and EnerG2’s Carbon Technology Platform has delivered a groundbreaking new product to this segment. This product will certainly play an important role in the world’s energy future, ultimately improving the performance of a wide variety of energy storage devices—everything from hybrid and electric vehicles, to industrial cranes and forklifts, to a cleaner and more efficient global energy grid.—Dr. Aaron Feaver
EnerG2 says that the benefits of its Li-ion anode materials include:
Enhancing the storage capacity of finished electrodes to provide a higher reversible lithium capacity versus other anode materials.
Increasing storage capacity and simultaneously improving the charge/discharge rate.
Designing and producing ultra-pure hard carbon products for rapid deployment into specific battery applications.
EnerG2 also said that its manufacturing approach has enabled the integration of advanced nano-scale silicon into EnerG2’s best-in-class hard carbon materials, providing a cohesive carbon-silicon nanocomposite anode material for significantly higher performance.
In developing the Carbon Technology platform, EnerG2—through rapid iteration of carbon morphologies and allotropes—identified the structural characteristics that are the most important to different electrochemical storage systems, and the means to produce them at a commercial scale.
In its 2012 DOE Merit Review presentation, for example, EnerG2 outlined four of its hard-carbon materials, each with different structural characteristics optimized for the application:
Ultracapacitor electrodes for EDV and HEV applications: V2 series for energy density and stability; and the P2 series for stability and power performance in any temperature range.
Lead acid batteries for micro-hybrid applications: M2-23 series for Highest performing in power, charge acceptance, and cycle life; and the M2-33 series for a match of power performance and cost effectiveness.
EnerG2 developed unique sol-gel processing technologies to construct its carbon materials. Sol-gel processing, which creates optimal structure and purity in the finished carbon product, is a chemical synthesis that gels colloidal suspensions to form solids through heat and catalysts.
EnerG2’s proprietary method controls the hydrolysis and condensation reactions within the gelling process, allowing the materials’ surface structures and pore-size distributions to be shaped, molded and customized for a variety of applications. EnerG2’s proprietary freeze-drying process to make its specialized carbon material was developed at the University of Washington.
EnerG2 operates the first and only manufacturing facility dedicated to the commercial-scale production of nano-engineered carbon material for high-performance energy storage applications. The 74,000 square foot plant—located in Albany Oregon—came online in February 2012.
The company’s ISO 9001:2008-certified facility in Albany is already producing advanced carbon materials at a multi-ton scale and is supplying commercial quantities to a growing, global customer base.