Calcium-organic frameworks cathode for high-stable aqueous Zn/organic batteries

Rechargeable aqueous zinc-ion batteries(AZIBs) are attracting tremendous attention because of their intrinsic merits such as high safety and low cost. Cathode plays a critical role in enhancing the electrochemical performance of AZIBs. However, it is difficult to design a robust and high-efficiency cathode material and further implement the commercialization of AZIBs. Metal-organic frameworks(MOFs) electroactive compounds are attractive to serve as the cathode of AZIBs due to their unique porosity and crystal structures, resource renewability and structural diversity. In this work, a calcium-pure terephthalates acid framework(Ca-PTA·3H_(2)O) was synthesized by facile hydrolysis and cationic exchange method,then explored as a novel cathode for AZIBs. The results highlight a high specific capacity of 431 mAh/g(0.51 mAh/cm^(2)) at a current density of 50 mA/g, and excellent cycle performance with capacity retention of ~90% after 2700 cycles at 500 m A/g. The following up characterizations investigate the reversible zinc storage mechanism in detail. This experiment made a specific contribution to the exploration of the new MOF as a competitive cathode for AZIBs.

Facile synthesis of T-Nb_2O_5 nanosheets/nitrogen and sulfur co-doped graphene for high performance lithium-ion hybrid supercapacitors

Li-ion hybrid supercapacitors（Li-HSCs） have attracted increasing attention as a promising energy storage device with both high power and energy densities. We report a facile two-step hydrothermal method to prepare the orthorhombic niobium oxide（T-Nb2O5） nanosheets supported on nitrogen and sulfur co-doped graphene（T-Nb205/NS-G） as anode for Li-HSCs. X-ray diffraction and morphological analysis show that the T-Nb2O5 nano sheets successfully and uniformly distributed on the NS-G sheets. The T-Nb2O5/NS-G hybrid exhibits great rate capability（capacity retention of63.1% from 0.05 to 5 A g^-1） and superior cycling stability（a low capacity fading of ～6.4% after 1000 cycles at 0.5 A g^-1）.The full-cell consisting of T-Nb2O5/NS-G and active carbon（AC） results in high energy density（69.2 W h kg^-1 at0.1 A g^-1）, high power density（9.17 kW kg^-1） and excellent cycling stability（95% of the initial energy after 3000 cycles）.This excellent performance is mainly attributed to the highly conductive NS-G sheets, the uniformly distributed T-Nb2O5 nano sheets and the synergetic effects between them. These encouraging performances confirm that the obtained TNb2O5/NS-G has promising prospect as the anode for Li-HSCs.

The Feasible Design of Quasi-Solid-State Aqueous Tin-Iodine Batteries

Aqueous rechargeable batteries with high safety have been considered as the main energy source to power portable and wearable electronics.Herein,we report the first construction of quasi-solid-state aqueous tin-iodine batteries by exploiting Sn foil as anode,carbon cloth as cathode,and gel electrolytes.The anode reversibly converts from K_(2)Sn(OH)_(6) to metal Sn,thus eliminating the formation of metal dendrites.Meanwhile,gel electrolytes alleviate anode corrosion and enhance the utilization of the anode.Therefore,the asfabricated quasi-solid-state batteries manifest an areal capacity of 700μAh cm^(-2)(211 mAh g^(-1) equal to theoretical capacity)and excellent cycling stability without obvious capacity degradation after 120 cycles at 1mA cm^(-2).Remarkably,the designed batteries sealed by different package materials including plastic,glass,wood,and cardboard operated steadily,thereby enlarging the application scenario for these batteries.This work enriches the family of aqueous rechargeable batteries and sheds light on the construction of high-performance quasi-solid-state aqueous batteries.