A　hierarchical　hollow　hybrid　composite,　namely,　MnO2　nanosheets　grown　on　nitrogen-doped　hollow　carbon　shells　(NHCSs@MnO2),　was　synthesized　by　a　facile　in　situ　growth　process　followed　by　calcination.　The　composite　has　a　high　surface　area　(251m(2)g(-1))　and　mesopores　(4.5nm　in　diameter),　which　can　efficiently　facilitate　transport　during　electrochemical　cycling.　Owing　to　the　synergistic　effect　of　NHCSs　and　MnO2,　the　composite　shows　a　high　specific　capacitance　of　306Fg(-1),　good　rate　capability,　and　an　excellent　cycling　stability　of　95.2%　after　5000　cycles　at　a　high　current　density　of　8Ag(-1).　More　importantly,　an　asymmetric　supercapacitor　(ASC)　assembled　by　using　NHCSs@MnO2　and　activated　carbon　as　the　positive　and　negative　electrodes　exhibits　high　specific　capacitance　(105.5Fg(-1)　at　0.5Ag(-1)　and　78.5Fg(-1)　at　10Ag(-1))　with　excellent　rate　capability,　achieves　a　maximum　energy　density　of　43.9Whkg(-1)　at　a　power　density　of　408Wkg(-1),　and　has　high　stability,　whereby　the　ASC　retains　81.4%　of　its　initial　capacitance　at　a　current　density　of　5Ag(-1)　after　4000　cycles.　Therefore,　the　NHCSs@MnO2　electrode　material　is　a　promising　candidate　for　future　energy-storage　systems.