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Transition metal oxides (TMOs) are considered favorable anode materials for lithium-ion batteries (LIBs); however, their poor conductivity, low-rate performance, and abrupt lithiated volumetric expansion make them unviable materials for a practical Li-ion full cell. As a prospective solution, a facile method of fabricating peanut-like porous carbon fibers (CFs) consisting of hollow carbon-coated NiCo–metal/oxide (NiCo–MO) spheres as high-performance anode (NiCo-MO@CFs) is reported. This synthesis route is simple and eco-friendly compared with the complicated synthesis of hollow TMOs, such as the hard template method, multistep route, or use of toxic reagents. The hollow structure can accommodate the abrupt lithiated volume variation of NiCo–MO, and the CFs can ensure structural durability during the discharge/charge process, offering a double buffering for the stress during volumetric fluctuation. A mechanistic study suggests that the hollow structure is formed by the typical Kirkendall diffusion, where encapsulation by CFs is a prerequisite. Outstanding Li-ion storage performance is supported by good rate capability and prolonged durability for 500 cycles at 1 A g−1 of NiCo-MO@CFs electrode. Remarkably, it shows a reversible discharge capacity of 894 mA h g−1 after the consecutive rate capability study and a successive discharge-charge process for 92 cycles at 0.1 A g−1. The computational study confirms that the most favorable Li adsorption sites for hybrid NiCo-MO@CFs surface are CoO-bridges and the hybrid surface provides enhanced Li adsorption energies and conductivity. Furthermore, a full cell was constructed using LiFePO 4 (cathode) and NiCo-MO@CFs (anode), which exhibits a discharge capacity of 616 mA h g−1 (anode-based) at 0.1 A g−1 with 66 % capacity retention after 100 cycles. [Display omitted] • Hollow NiCo-metal/oxide (MO)@carbon fibers (CFs) was made as anodes for LIBs. • NiCo-MO@CFs delivered the stable discharge capacities of 832 mA h g−1 at 0.1 A g−1. • After 500 cycle, NiCo-MO@CFs exhibited 96 % of capacity retention at 1 A g−1. • DFT shows fast charge-discharge rate with suitable diffusion energy barrier for Li+. • NiCo-MO@CFs-based full-cell shows a capacity 616 mA h g−1 and good stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The active sites-rich Ni-Co-P@C/Ni-B material enables fast transfer of electron/ion. • DFT results verify stable OH* adsorption energy and metallic nature of the hybrid. • The Ni-Co-P@C/Ni-B shows a high specific capacity of 306 mAh g−1 at 3 mA cm−2. • Highly porous N-doped C nanofibers with nanocages was made as negative electrode. • The hybrid supercapacitor device shows 68.3 Wh kg−1 energy density at 472 W kg−1. In recent times, a lot of research effort has been performed to develop hybrid supercapacitors (HSCs) because of their ability to produce high energy density as well as superb power density. The key issue for realizing high-performance HSCs is to minimize the kinetic mismatch between rapid capacitor-type anode and sluggish battery-type cathode. Optimizing the interface, morphology and microstructure of the electrode material is a favorable approach to surmount kinetic imbalance. Herein, a core–shell nanoarrays of ultrathin carbon layer-coated crystalline Ni-Co-phosphide (Ni-Co-P@C) and amorphous Ni-boride (Ni-B) is fabricated on a nickel foam substrate as a positive electrode material (Ni-Co-P@C/Ni-B). Theoretical analyses validate the best metallic characteristic and most stable OH* absorption energy for Ni-Co-P@C/Ni-B, which enhance its charge storage performance than analogous Ni-Co-P and Ni-Co-P/Ni-B. The porous nitrogen (N)-doped carbon (C) nanofibers consisting of tightly embedded metal–organic framework (ZIF-8)-derived interconnected N-C nanocages (HP-N-CFs) showed excellent charge storage kinetics as a negative electrode. The battery-type Ni-Co-P@C/Ni-B electrode revealed a specific capacity of 306.2 mA h g−1 at 3 mA cm−2, while highly porous capacitive HP-N-CFs electrode showed the highest capacity of 56 mA h g−1 at 2.5 mA cm−2. In addition, the assembled quasi-solid-state (Ni-Co-P@C/Ni-B//HP-N-CFs) HSCs exhibited the highest energy density of 68.3 W h kg−1 at a power density of 472 W kg−1 with a superb rate capability (68% at 50 mA cm−2) and decent cyclic durability (90% retention over 10,000 cycles). [ABSTRACT FROM AUTHOR]