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Self-Generated Nanoporous Silver Framework for High-Performance Iron Oxide Pseudocapacitor Anodes

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journal contribution
posted on 04.05.2018, 00:00 by Jae Young Seok, Jaehak Lee, Minyang Yang
The rapid development of electric vehicles is increasing the demand for next-generation fast-charging energy storage devices with a high capacity and long-term stability. Metal oxide/hydroxide pseudocapacitors are the most promising technology because they show a theoretical capacitance that is 10–100 times higher than that of conventional supercapacitors and rate capability and long-term stability that are much higher than those of Li-ion batteries. However, the poor electrical conductivity of metal oxides/hydroxides is a serious obstacle for achieving the theoretical pseudocapacitor performance. Here, a nanoporous silver (np-Ag) structure with a tunable pore size and ligament is developed using a new silver halide electroreduction process. The structural characteristics of np-Ag (e.g., large specific surface area, electric conductivity, and porosity) are desirable for metal oxide-based pseudocapacitors. This work demonstrates an ultra-high-capacity, fast-charging, and long-term cycling pseudocapacitor anode via the development of an np-Ag framework and deposition of a thin layer of Fe2O3 on its surface (np-Ag@Fe2O3). The np-Ag@Fe2O3 anode shows a capacitance of ∼608 F g–1 at 10 A g–1, and ∼84.9% of the capacitance is retained after 6000 charge–discharge cycles. This stable and high-capacity anode, which can be charged within a few tens of seconds, is a promising candidate for next-generation energy storage devices.