An Ultrafast Rechargeable Aluminum-Graphene Foam Battery

Chang-Chung YANG, Industrial Technology Research Institute (ITRI), Taiwan

Developed under collaborative efforts from ITRI and Stanford University, the first commercially viable aluminum battery, was born. The battery uses an aluminum anode, a graphite-structured carbon cathode, and a highly safe ionic liquid electrolyte. It is capable of ramping between 100% and 20% full capacity in two-minute repeatedly for more than 10,000 cycles, while maintaining an exceptional coulombic efficiency (CE) of 98% throughout a cycle life.

Mainstream battery technologies nowadays usually use lithium. However, lithium is limited in abundance, and is expensive and chemically unstable. It is not ideal for heavy duty applications that automobile or power industries need. Aluminum, on the other hand, constitutes an incredible 8.2% of the Earth’s crust, making it ideal for meeting large scale demands in energy storage and clean mobility of the future.

The aluminum battery has many advantageous properties, such as its use of naturally abundant raw materials, leading to lower manufacturing costs. Using a flexible 3D graphene foam as cathode materials which was made on a nickel foam template by chemical vapor deposition. The graphite backbones in the foam were 100 μm in width, with large spaces in between, which greatly decreased the diffusion length for the intercalating electrolyte anions and facilitated more rapid battery operation. Analysis of XRD spectrums suggested a stage 4 graphite intercalation compound with an intercalant gallery height (spacing between adjacent graphitic host layers) of 5.7 Å indicating that the AlCl4 anions (size ~ 5.28 Å) were intercalated between graphene layers in a distorted state.

The aluminum battery also has a long cycle life, is ultrafast (more than 125 C rate, < 30 second charge/discharge time), and has efficient charging/discharging characteristics. In addition, it is inherently safe, and environmentally friendly. Because of these merits, the aluminum battery can find universal applications in renewable energy storage, electrical cars, power tools, and portable electronic products. The aluminum battery has great durability, and can be recharged up to 10,000 times while maintaining excellent capacity. It can be charged much quicker than lithium-ion batteries. It can be fully charged in 1 minute in any devices. Therefore, the scenario of charging a device may no longer be tied to definitive places like home or office, but anywhere, anytime.

The battery’s stability can be attributed to aluminum’s deposit (charge) / dissolve (discharge) reaction within ionized liquid of up to 99.8% coulombic efficiency. The anode does not cause dendritic crystallization which quickly damages conventional batteries. The aluminum battery is inherently safe, because all components in the battery system, including the aluminum and graphite electrodes, and the isolating membrane, are inert. Ionic liquids are eco-friendly solvents because of their low volatility, non-toxicity, and non-flammable nature.

This breakthrough battery technology will compete with the traditional lead acid battery when applied in large energy storage devices, lightweight electric scooters, and motorized bicycles. In addition to small smart devices, the aluminum batteries can be used to store renewable energy in electricity grids, electric motorcycles and bicycles. The aluminum battery is the first electrochemical device capable of achieving a storage cost lower than a quarter of the cost of renewable electricity itself.

 
Back to TS.VIII.C