Oxygen‑Defect Enhanced Anion Adsorption Energy Toward Super‑Rate and Durable Cathode for Ni–Zn Batteries

The alkaline zinc-based batteries with high energy density are becoming a research hotspot.However,the poor cycle stability and low-rate performance limit their wide application.Herein,ultra-thin CoNiO2 nanosheet with rich oxygen defects anchored on the vertically arranged Ni nanotube arrays(Od-CNO@Ni NTs)is used as a positive material for rechargeable alkaline Ni–Zn batteries.As the highly uniform Ni nanotube arrays provide a fast electron/ion transport path and abundant active sites,the Od-CNO@Ni NTs electrode delivers excellent capacity(432.7 mAh g^(−1))and rate capability(218.3 mAh g^(−1) at 60 A g^(−1)).Moreover,our Od-CNO@Ni NTs//Zn battery is capable of an ultra-long lifespan(93.0%of initial capacity after 5000 cycles),extremely high energy density of 547.5 Wh kg^(−1) and power density of 92.9 kW kg^(−1)(based on the mass of cathode active substance).Meanwhile,the theoretical calculations reveal that the oxygen defects can enhance the interaction between electrode surface and electrolyte ions,contributing to higher capacity.This work opens a reasonable idea for the development of ultra-durable,ultra-fast,and high-energy Ni–Zn battery.

Promoting Proton Migration Kinetics by Ni^(2+)Regulating Enables Improved Aqueous Zn-MnO_(2) Batteries

The energy storage behaviors of MnO_(2) for aqueous Zn-MnO_(2) batteries mainly depend on the Zn^(2+)/H^(+)intercalation but are limited by poor ion/electron migration dynamics and stability.Herein,a strategy is proposed that promoting proton migration kinetics ameliorates H^(+)storage activity by introducing Ni^(2+)intoγ-MnO_(2)(Ni-MnO_(2)).Ni^(2+)can lower the diffusion barrier of H^(+)and selectively induce the ion intercalation,thereby alleviating the electrostatic interaction with the lattice.Moreover,Ni^(2+)enables the adjacent[MnO6]octahedrons to have better electron conductivity.The Ni-MnO_(2) exhibits superior rate performance(nearly four times specific capacity compared with MnO_(2))and ultra-long-cycle stability(100%of capacity retention after 11000 cycles at 3.0 A g^(-1)).The calculation indicates that the Ni-MnO_(2) allows H^(+)migrate rapidly along the one-dimensional tunnel due to reduction of the activation energy caused by Ni^(2+)regulating,thus achieving excellent reaction kinetics.This work brings great potential for the development of high-performance aqueous Zn-MnO_(2) batteries.

Favorable anion adsorption/desorption of high rate NiSe_(2) nanosheets/hollow mesoporous carbon for battery-supercapacitor hybrid devices

High-rate battery-type cathode materials have attracted wide attention for advanced battery-supercapacitor hybrid(BSH)devices.Herein,a core-shell structure of the hollow mesoporous carbon spheres(HMCS)supported NiSe2 nanosheets(HMCS/NiSe2)is constructed through two-step reactions.The HMCS/NiSe_(2)shows a max specific capacity of 1,153.5 C·g^(-1) at the current density of 1 A·g^(-1),and can remain at 774.5 C·g^(-1) even at 40 A·g^(-1)(the retention rate as high as 67.1%)and then the HMCS/NiSe_(2) electrode can keep 80.5%specific capacity after 5,000 cycles at a current density of 10 A·g^(-1).Moreover,the density functional theory(DFT)calculation confirmed that the introduction HMCS into NiSe_(2) made adsorption/desorption of OH-easier,which can achieve higher rate capability.The HMCS/NiSe_(2)//6 M KOH//HMCS hybrid device has energy density of 47.15 Wh·kg^(-1) and power density of 801.8 W·kg^(-1).This work provides a feasible electrode material with a high rate and its preparation method for high energy density and power density energy storage devices.