Acquisition of high-energy density is the highest priority requirement and unending challenge in energy storage systems including lithium-ion batteries (LIBs). One theoretically preferable way to reach this goal is the use of cathode active materials such as vanadium pentoxide (V2O5) that relies on multielectron insertion/extraction reactions. Application of V2O5 to LIB cathodes, however, has been mostly focused on V2O5 materials themselves with little emphasis on V2O5-incorporated cathode sheets. Here, as an unusual electrode-architecture approach to achieve ultrahigh-capacity V2O5 cathode sheets, a new class of self-standing V2O5 cathode sheets is demonstrated based on V2O5/multiwalled carbon tubes (MWNTs) mixtures spatially besieged by polyacrylonitrile nanofibers (referred to as "VMP cathode sheets"). Notably, the VMP cathode sheet is fabricated directly via one-pot synthetic route starting from V2O5 precursor (i.e., through concurrent electro-spraying/electrospinning followed by calcination), without metallic foil current collectors/carbon powders/polymeric binders. The one-pot synthesis allows dense packing of V2O5 nanoparticles in close contact with MWNT electronic networks and also formation of well-developed interstitial void channels (ensuring good electrolyte accessibility). This material/architecture uniqueness of the VMP cathode sheet eventually enables significant improvements in cell performance (particularly, gravimetric/volumetric capacity of cathode sheets) far beyond those accessible with conventional electrode technologies.