Metal-ion capacitors (MICs) are suitable for applications where high energy density along with high power is needed, e.g., regenerative braking, stop/start systems, or peak-power shaving . In such applications, a high-power performance is desirable to relieve the coupled battery system from stress during peak power demand and enhance its operational life . Therefore, new materials with fast charge/discharge characteristics are needed to improve the rates at which energy is stored and delivered.