Energy Storage Update

November 15, 2011 | News

The zinc-nickel system developed at the CUNY Energy Institute has achieved 3,000 cycles (and counting).

For the past two years, the CUNY Energy Institute team under Professor Sanjoy Banerjee has been working to develop zinc anode rechargeable batteries for grid-scale storage applications. We see a critical need for this infrastructure in the United States and abroad. The U.S. grid for electricity generation and delivery is too vulnerable to disruption to support renewable but intermittent energy sources like solar and wind. Lacking significant storage, the grid requires that the energy supplied by power plants match customer demand in real time. Electricity storage is needed to balance the grid, but its high cost has prevented widespread adoption in this country until now.

Energy storage research is experiencing something of a renaissance right now, largely due to the leadership of the Department of Energy’s Advanced Research Project Agency-Energy (ARPA-E) and forward-thinking state governments. With the support of ARPA-E, NYSERDA, and Con Edison, we are developing zinc anode rechargeable batteries for grid scale applications. Our energy storage solutions are safe, non-flammable, and low-cost with a long cycle life.

Flowing electrolyte helps keep dendrites from forming in this Zn-MnO2 battery.

Our starting materials, Zinc (Zn) and manganese dioxide (MnO2), are used in traditional disposable batteries; they are non-toxic, abundant, and inexpensive, with good energy densities. The challenge so far has been to make a Zn-MnO2 battery that is rechargeable for thousands of cycles. Without patent-pending technology from the CUNY Energy Institute, Zn cells develop solid precipitates called dendrites that eventually cause the cells to short out, while MnO2 cells rapidly lose the ability to hold charge. We have overcome the limitations of our starting materials using the breakthrough innovation of electrolyte flow.

At the CUNY Energy Institute, we are currently examining a 1.6kWh Zn anode module that has been tested through 3,000 cycles (and counting) and an MnO2 cell that can undergo 1,000 discharge cycles at $100/kWh. We plan to scale up in the near future and demonstrate a 50kWh grid-connected battery by the end of 2012.