Abstract: An energy storage device including an anode, a cathode, at least one of the anode and the cathode including a carbon nanosheet having an active material, such as selenium, in and/or on the carbon nanosheet, and an electrolyte. A carbon material including a carbon nanosheet derived from a biological precursor, such as nanocrystalline cellulose, including a plurality of micropores and an active material impregnated into at least a portion of the micropores of the carbon nanosheet.

Abstract: An energy storage device, such as a sodium ion capacitor, including an anode and a cathode, at least one of the anode and the cathode including a nitrogen and oxygen functionalized carbon (NOFC). The NOFC has a nitrogen content greater than 4 wt %, such as 13 wt %, an oxygen content greater than 8 wt %, such as 11 wt %, and a surface area greater than 800 m2g?1, such as 945 m2g?1. The energy storage device has favorable reversible and rate capability, such as 437 mAhg?1 at 100 mAg?1, and 185 mAhg?1 at 1600 mA g?1.

Abstract: Carbon nanosheets fabricated by carbonization and activation or by carbonization alone. The nanosheets possess a disordered structure for copious reversible binding of ions at the carbon defects. They are also hierarchically micro-meso-macro porous, allowing facile ion transport at high rates both through the pore-filling electrolyte and in the solid-state. Also, a combined battery—supercapacitor energy storage device using the carbon nanosheets as one or both of the electrodes therein. Tuning the mass-loading ratio of the carbon nanosheets in the two electrodes configures the carbon nanosheets to operate either as a bulk insertion electrode (anode) or a surface adsorption electrode (cathode). The energy storage device may further include a housing with a form factor of a commercial battery.

Abstract: An anode for a battery including an electrochemically active material including a ternary alloy of tin (Sn), germanium (Ge), and antimony (Sb). A battery including the anode, a cathode, a separator, and an electrolyte. The ternary alloy may include SnxGeySbz, where x+y+z=100, and x?y or x?z. The alloy may include a multiphase microstructure with an amorphous phase and nanocrystalline phase, each of the phases being ion active.

Abstract: An energy storage device, such as a sodium ion capacitor, including an anode and a cathode, at least one of the anode and the cathode including a nitrogen and oxygen functionalized carbon (NOFC). The NOFC has a nitrogen content greater than 4 wt %, such as 13 wt %, an oxygen content greater than 8 wt %, such as 11 wt %, and a surface area greater than 800 m2g?1, such as 945 m2g?1. The energy storage device has favorable reversible and rate capability, such as 437 mAhg?1 at 100 mAg?1, and 185 mAhg?1 at 1600 mA g?1.