An in-situ self-etching enabled high-power electrode for aqueous zinc-ion batteries

Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.

3D Artificial Array Interface Engineering Enabling Dendrite-Free Stable Zn Metal Anode

The ripple effect induced by uncontrollable Zn deposition is considered as the Achilles heel for developing high-performance aqueous Zn-ion batteries.For this problem,this work reports a design concept of 3D artificial array interface engineering to achieve volume stress elimination,preferred orientation growth and dendrite-free stable Zn metal anode.The mechanism of MXene array interface on modulating the growth kinetics and deposition behavior of Zn atoms were firstly disclosed on the multi-scale level,including the in-situ optical microscopy and transient simulation at the mesoscopic scale,in-situ Raman spectroscopy and in-situ X-ray diffraction at the microscopic scale,as well as density functional theory calculation at the atomic scale.As indicated by the electrochemical performance tests,such engineered electrode exhibits the comprehensive enhancements not only in the resistance of corrosion and hydrogen evolution,but also the rate capability and cyclic stability.High-rate performance(20 mA cm^(-2))and durable cycle lifespan(1350 h at 0.5 mA cm^(-2),1500 h at 1 mA cm^(-2)and 800 h at 5 mA cm^(-2))can be realized.Moreover,the improvement of rate capability(214.1 mAh g^(-1)obtained at 10 A g^(-1))and cyclic stability also can be demonstrated in the case of 3D MXene array@Zn/VO2battery.Beyond the previous 2D closed interface engineering,this research offers a unique 3D open array interface engineering to stabilize Zn metal anode,the controllable Zn deposition mechanism revealed is also expected to deepen the fundamental of rechargeable batteries including but not limited to aqueous Zn metal batteries.

A Multifunctional Anti-Proton Electrolyte for High-Rate and Super-Stable Aqueous Zn-Vanadium Oxide Battery

Large volumetric expansion of cathode hosts and sluggish transport kinetics in the cathode–electrolyte interface,as well as dendrite growth and hydrogen evolution at Zn anode side are considered as the system problems that cause the electrochemical failure of aqueous Zn-vanadium oxide battery.In this work,a multifunctional anti-proton electrolyte was proposed to synchronously solve all those issues.Theoretical and experimental studies confirm that PEG 400 additive can regulate the Zn^(2+) solvation structure and inhibit the ionization of free water molecules of the electrolyte.Then,smaller lattice expansion of vanadium oxide hosts and less associated by-product formation can be realized by using such electrolyte.Besides,such electrolyte is also beneficial to guide the uniform Zn deposition and suppress the side reaction of hydrogen evolution.Owing to the integrated synergetic modifica-tion,a high-rate and ultrastable aqueous Zn-V_(2)O_(3)/C battery can be constructed,which can remain a specific capacity of 222.8 m Ah g^(-1)after 6000 cycles at 5 A g^(-1),and 121.8 m Ah g^(-1) even after 18,000 cycles at 20 A g^(-1),respectively.Such“all-in-one”solution based on the electrolyte design provides a new strategy for developing high-performance aqueous Zn-ion battery.