N-doped carbon foam based three-dimensional electrode architectures and asymmetric supercapacitors†
Improving the electrochemical performance of supercapacitors mainly depends on the electrode design and system construction. A new kind of additive-free asymmetric supercapacitors (ASCs) has been successfully fabricated using a self-supported carbon foam/ordered mesoporous carbon (CF-OMC) film as the negative electrode and free-standing CF-NiCo2O4 nanosheets (NSs) as the positive electrode, respectively. The highly conductive three-dimensional (3D) CF framework could facilitate electron transfer while the porous thin film of OMC and ultrathin NiCo2O4 nanosheets could shorten the ion diffusion path and facilitate the rapid migration of electrolyte ions. The optimized asymmetric supercapacitors could work with an operational voltage of 1.6 V, delivering a high energy density (∼47.8 W h kg−1), high power density (∼9800 W kg−1 at 17.7 W h kg−1) and outstanding cycle stability (∼10 000 times). This research may pave the way for fabricating lightweight, low-cost, and high-performance electrodes for energy storage applications.