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Key Words:LONG-CYCLE-LIFE; RATE CAPABILITY; ENERGY-STORAGE; PERFORMANCE; ELECTRODE; MICROSPHERES; CONSTRUCTION; DENSITY
Abstract:The poor rate capability and low capacity are huge barriers to realize the commercial applications of battery-type transition metal compounds (TMCs) cathode. Herein, numerous Se vacancy defects are introduced into the Ni3Se2 lamellas by pre-lithiation technique, which can be acted as a novel class of battery-type cathode for hybrid supercapacitors. Appropriately modulating the contents of the pre-embedded lithium (Li) ions can induce a controllable vacancy content in the series of as-prepared prod-ucts, effectively endowing a fast reaction kinetic and high activity for the cathode. Benefiting from the distinct design, the optimized cathode (Li2-Ni3Se2) presents a high specific capacity of 236 mA h g-1 at 1 A g-1, importantly, it can still possess 117 mA h g-1 when the current density is increased up to 100 A g-1, exhibiting relatively high rate capability. It is much superior to other battery-type TMC cathodes reported in previous studies. Moreover, the cathode also shows the excellent cycling stability with 92% capacity retention after 3,000 cycles. In addition, a hybrid supercapacitor (HSC) is assembled with the obtained Li2-Ni3Se2 as the cathode and active carbon (AC) as the anode, which delivers a high energy den-sity of 77 W h kg-1 at 4 kW kg-1 and long-term durability (90% capacitance retention after 10,000 cycles). Therefore, the strategy not only provides an effective way to realize the controllable vacancy content in TMCs for achieving high-performance cathodes for HSC, but also further promotes their large-scale appli-cations in the energy storage fields. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.
Volume:78
Issue:-
Translation or Not:no