A research team at Stanford University has designed a novel electrode made of copper crystalline nanoparticles, paving the way to develop a durable, highly efficient, high-power rechargeable battery that is capable of storing huge amount of surplus power produced during sunny and windy days.
The research offers a promising solution to the problem of sharp drop-offs in the output of wind and solar systems with minor changes in weather conditions.
During lab experiments, the electrode was able to be charged and discharged for 40,000 cycles, after which it can still be charged to over 80% of its initial charge capacity. The crystalline copper hexacyanoferrate’s atomic structure is the reason behind the superior durability of the electrode. The open structure of the crystals makes ions or electrically charged particles to travel easily and freely through the electrode without causing damage to it.
The rate of movement of the ions will affect the rate of charging and discharging of a battery. Since the innovative electrode’s structure allows the ions to travel freely, it has ultrafast cycle of charging and discharging, a key factor in the design of a rechargeable battery. The open strucutre’s advantage is optimized through the use of hydrated potassium ions, which have the correct size that facilitate their free movement.
The electrode’s speed is significantly enhanced, as the size of the electrode particles is of the order of just 100 atoms across. The size advantage also allows the ions to quickly reach the active spots in a particle for reaction with them for charging the electrode to its optimal capacity, or to leave the active sites quickly for rapid discharging. The research team used an aqueous electrolyte and materials such as nitrogen, carbon, copper and iron as the battery electric materials.
The new electrode’s chemical properties make it be used as a high-voltage electrode, which is its major drawback. Hence, the research team needs to identify a suitable material that can be used the anode to develop an actual battery. The team has identified some promising candidates for the anode. According the team, the lab process can easily be adopted for commercial-scale production of the electrode material.
Source: http://news.stanford.edu