A Flexible Supercapacitor with High True Performance

The demand for better "true performance" of supercapacitors, which is defined as the energy density based on the packaged cell with high active mass loading, is spurred by the ever-increasing energy storage market. The true performance of present supercapacitors is unsatisfactory, greatly limited by the currently used current collectors. Here, we develop a through-pore structured nickel current collector with excellent flexibility by electrodepositing nickel on laser-drilled stainless steel sheets filled with epoxy resin. Based on the new current collector, the electrodes possess higher performance than those fabricated by employing conventional current collectors. At a high active mass loading, the assembled supercapacitors show superior flexibility and high energy densities of 50.4 W hr L^-1 and 30.1 W hr kg^-1, respectively, based on the packaged cell, outperforming the present supercapacitors. Our strategy provides a new opportunity for promoting the further development of supercapacitors by enhancing the true performance.