Cyclohexanedodecol-Assisted Interfacial Engineering for Robust and High-Performance Zinc Metal Anode

Aqueous zinc-ion batteries(AZIBs)can be one of the most promising electrochemical energy storage devices for being non-flammable,low-cost,and sustainable.However,the challenges of AZIBs,including dendrite growth,hydrogen evolution,corrosion,and passivation of zinc anode during charging and discharging processes,must be overcome to achieve high cycling performance and stability in practical applications.In this work,we utilize a dual-func-tional organic additive cyclohexanedodecol(CHD)to firstly establish[Zn(H2O)5(CHD)]2+complex ion in an aqueous Zn electrolyte and secondly build a robust protection layer on the Zn surface to overcome these dilemmas.Systematic experiments and theoretical calculations are carried out to interpret the working mechanism of CHD.At a very low concentration of 0.1 mg mL^(−1) CHD,long-term reversible Zn plating/stripping could be achieved up to 2200 h at 2 mA cm^(−2),1000 h at 5 mA cm^(−2),and 650 h at 10 mA cm^(−2) at the fixed capacity of 1 mAh cm^(−2).When matched with V_(2)O_(5) cathode,the resultant AZIBs full cell with the CHD-modified electrolyte presents a high capacity of 175 mAh g^(−1) with the capacity retention of 92%after 2000 cycles under 2 A g^(−1).Such a performance could enable the commercialization of AZIBs for applications in grid energy storage and industrial energy storage.

Amylopectin from Glutinous Rice as a Sustainable Binder for High-Performance Silicon Anodes

Silicon(Si)has been investigated as a promising anode material because of its high theoretical capacity(4200 m Ah g^(-1)).However,silicon anode suffers from huge volume changes during repeated charge–discharge cycles.In this work,inspired by a remarkable success of the glutinous rice mortar in the Great Wall with ca.2000-year history,amylopectin(AP),the key ingredient responsible for the strong bonding force,is extracted from glutinous rice and utilized as a flexible,aqueous,and resilient binder to address the most challenging drastic volume-expansion and pulverization issues of silicon anode.Additionally,the removal of toxic N-methyl-2-pyrrolidone(NMP)organic solvent makes the electrode fabrication process environmentally friendly and healthy.The as-prepared Si-AP electrode with 60 wt%of Si can uphold a high discharge capacity of 1517.9 m Ah g^(-1)at a rate of 0.1 C after 100 cycles.The cycling stability of the Si-AP has been remarkably improved in comparison with both traditional polyvinylidene fluoride(PVDF)and aqueous carboxymethylcellulose(CMC)binders.Moreover,when the content of silicon in the Si-AP electrode increases to 70 wt%,a high discharge capacity of 1463.1 m Ah g^(-1)can still be obtained after 50 cycles at 0.1°C.These preliminary results suggest that the sustainably available and environmentally benign amylopectin binders could be a promising choice for the construction of highly stable silicon anodes.

Poly(thiourea triethylene glycol) as a multifunctional binder for enhanced performance in lithium-sulfur batteries

A mechanically strong binder with polar functional groups could overcome the dilemma of the large volume change during charge/discharge processes and poor cyclability of lithium-sulfur batteries(LSBs).In this work,for the first time,we report the use of poly(thiourea triethylene glycol)(PTTG)as a multifunctional binder for sulfur cathodes to enhance the performance of LSBs.As expected,the PTTG binder facilitates the high performance and stability delivered by the Sulfur-PTTG cathode,including a higher reversible capacity of 825 mAh g^(-1) at 0.2 C after 80 cycles,a lower capacity fading(0.123%per cycle)over 350 cycles at 0.5 C,a higher areal capacity of 2.5 mAh cm^(-2) at 0.25 mA cm^(-2),and better rate capability of 587 mAh g^(-1) at 2 C.Such superior electrochemical performances could be attributed to PTTG's strong chemical adsorption towards polysulfides which may avoid the lithium polysulfide shuttle effect and excellent mechanical characteristics which prevents electrode collapse during cycling and allows the Sulfur-PTTG electrode to maintain robust electron and ion migration pathways for accelerated redox reaction kinetics.