High-Power and Ultralong-Life Aqueous Zinc-Ion Hybrid Capacitors Based on Pseudocapacitive Charge Storage.

ABSTRACT: Rechargeable aqueous zinc-ion hybrid capacitors and zinc-ion batteries are promising safe energy storage systems. In this study, amorphous RuO₂·H₂O for the first time was employed to achieve fast and ultralong-life Zn²⁺ storage based on a pseudocapacitive storage mechanism. In the RuO₂·H₂O||Zn zinc-ion hybrid capacitors with Zn(CF₃SO₃)₂ aqueous electrolyte, the RuO₂·H₂O cathode can reversibly store Zn²⁺ in a voltage window of 0.4-1.6 V (vs. Zn/Zn²⁺), delivering a high discharge capacity of 122 mAh g^-1. In particular, the zinc-ion hybrid capacitors can be rapidly charged/discharged within 36 s with a very high power density of 16.74 kW kg^-1 and a high energy density of 82 Wh kg^-1. Besides, the zinc-ion hybrid capacitors demonstrate an ultralong cycle life (over 10,000 charge/discharge cycles). The kinetic analysis elucidates that the ultrafast Zn²⁺ storage in the RuO₂·H₂O cathode originates from redox pseudocapacitive reactions. This work could greatly facilitate the development of high-power and safe electrochemical energy storage.

SUBMITTER: Dong L 

PROVIDER: S-EPMC7770721 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature