Sr-doped urchin-like NiCo hydroxide and Sr-doped flower-like NiCo hydroxide@O-doped layered porous carbon for high-performance asymmetric supercapacitors with gel electrolyte

In order to improve the engineering practicability and cyclic stability of electrode material, the biomass-based porous carbon is designed as the solid substrate to load the mixed metal hydroxide. O-doped layered porous carbon is prepared from bagasse pith by chemical activation. Its flat and broad surface is ideal for loading metal hydroxide. A simple strategy is devised to synthesize Sr-doped urchin-like NiCo hydroxide (U-SrNiCo-OH) and Sr-doped flower-like NiCo [email protected] layered porous carbon ([email protected]). The U-SrNiCo-OH electrode shows high specific capacity (616.69 C g−1 at 1 A g−1 and 425.00 C g−1 at 50 A g−1) and excellent rate performance (68.92 % retention from 1 A g−1 to 50 A g−1). Compared with the U-SrNiCo-OH electrode, the F-SrNi[email protected] electrode exhibits close specific capacity (584.16 C g−1 at 1 A g−1 and 341.66 C g−1 at 50 A g−1) and higher cyclic stability (63.59 % retention after 5000 cycles). When used as the positive material, F-SrNiCo-O[email protected] performs best. In the gel electrolyte, the asymmetric supercapacitor based on [email protected] delivers high specific capacitance (93.60 F g−1 at 0.5 A g−1 and 47.00 F g−1 at 10 A g−1) and high energy density (29.12 W h kg−1 at 374.14 W kg−1). Based on the molecular dynamics (MD) simulations, the OLPC configuration with microporous structure similar to that of OLPC is constructed, and the charging dynamics of asymmetric supercapacitor is studied. [email protected], with low cost and excellent electrochemical performance, has great application potential in energy storage/conversion. The MD simulations provide a new perspective for understanding the energy storage process of asymmetric supercapacitor.