Acceleration of bidirectional sulfur conversion kinetics and inhibition of lithium dendrites growth via a“ligand-induced”transformation strategy

The introduction of materials with dual-functionalities,i.e.,the catalytic(adsorption)features to inhibit shuttle effects at the cathode side,and the capability to facilitate homogenous Li-ion fluxes at the anode side,is a promising strategy to realize high performance lithium-sulfur batteries(LSBs).Herein,a facile and rational organic“ligand-induced”(trimesic acid(TMA))transformation tactic is proposed,which achieves the regulation of electronic performance and d-band center of bimetallic oxides(NiFe_(2)O_(4))to promote bidirectional sulfur conversion kinetics and stabilize the Li plating/striping during the charge/discharge process.The battery assembled with NiFe_(2)O_(4)-TMA modified separator exhibits a remarkable initial specific capacity of 1476.6 mAh·g^(-1)at 0.1 C,outstanding rate properties(661.1 mAh·g^(-1)at 8.0 C),and excellent cycling ability.The“ligand-induced”transformation tactic proposed in this work will open a whole new possibility for tuning the electronic structure and d-band center to enhance the performance of LSBs.

The design of Co_(3)S_(4)@MXene heterostructure as sulfur host to promote the electrochemical kinetics for reversible magnesium-sulfur batteries

The rechargeable Mg-S batteries are attractive because of their resource abundances of Mg and S,high volumetric energy density,and less dendrite property of Mg anodes.However,the development is barred by the intrinsic low electronic conductivity of S and the discharge products as well as the lack of understanding the hidden electrochemical kinetics.Here,a Co_(3)S_(4)@MXene heterostructure is proposed as effective sulfur host for reversible Mg-S batteries.XPS results and density functional theory(DFT)calculation confirm that the chemical interaction between the decorated Co_(3)S_(4)nanocrystals host and polysulfide intermediates could well absorb and catalyze the polysulfides conversion,thus improve the electrochemical redox kinetics.Meanwhile,the MXene matrix could promote Mg ion diffusion dynamics greatly.As a result,the developed Mg-S batteries using the Co_(3)S_(4)@MXene-S as the cathode material could demonstrate high sulfur utilization with specific capacity of 1220 mAh g^(-1) and retain a capacity of 528 mAh g^(-1) after 100 cycles,together with a satisfactory rate performance even at 2 C.This work shed light on the advanced cathode design for reversible high energy Mg-S batteries.

Enhancing sulfur cathode process via a functionalized complex molecule

Lithium-sulfur batteries are regarded as promising next-generation energy storage batteries for their ultra-high theoretical energy density.However,the complex sulfur electrode process with sluggish sulfur conversion reactions is a critical issue for lithiumsulfur batteries,in which catalytic interfacial reactions and accelerated lithium-ion diffusion are the key factors.Our previous work has shown that implanting functional molecules with multiple redox properties in the electrode can break through the conventional diffusion layer constraints and achieve forced convection.In this work,a functionalized complex molecule,methylene blue anthraquinone-2-sulfonate(MB-AQ),with multiple redox activities as well as abundant active sites,was synthesized and introduced into the sulfur cathode.In addition to accelerating the transport of lithium ions by reversible inhaling and exhaling lithium ions,the MB-AQ can combine polysulfides by its active sites to accelerate sulfur conversion reactions.Benefiting from two functions of accelerating ion diffusion and catalyzing interfacial reactions,MB-AQ/reduced graphene oxide(rGO)/S cathode can achieve high initial capacities of 884 and 674 mAh·g^(−1)with stable cycling of 700 and 1,000 times at 1 and 4 C,respectively.It is worth mentioning that the capacity of 462 mAh·g^(−1)can be achieved even at a high current density of 6 C.This work provides a new approach to enhancing the sulfur cathode process.

Synergistic effects of chemical additives and mature compost on reducing H_2S emission during kitchen waste composting

Additives could improve composting performance and reduce gaseous emission,but few studies have explored the synergistic of additives on H_(2)S emission and compost maturity.This research aims to make an investigation about the effects of chemical additives and mature compost on H_(2)S emission and compost maturity of kitchen waste composting.The results showed that additives increased the germination index value and H_(2)S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H_(2)S emission reduction(85%).Except for the treatment with only chemical additives,the total sulfur content increased during the kitchen waste composting.The proportion of effective sulfur was higher with the addition of chemical additives,compared with other groups.The relative abundance of H_(2)S-formation bacterial(Desulfovibrio)was reduced and the relative abundance of bacterial(Pseudomonas and Paracoccus),which could convert sulfur-containing substances and H_(2)S to sulfate was improved with additives.In the composting process with both chemical additives and mature compost,the relative abundance of Desulfovibrio was lowest,while the relative abundance of Pseudomonas and Paracoccus was highest.Taken together,the chemical additives and mature compost achieved H_(2)S emission reduction by regulating the dynamics of microbial community.

In situ protection of a sulfur cathode and a lithium anode via adopting a fluorinated electrolyte for stable lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical energy density and low material cost.However,the conventional ether-based electrolytes of Li-S batteries are extremely flammable and have high solubility of lithium polysulfides(LiPS),resulting in a high safety risk and a poor life cycle.Herein,we report an ether/carbonate co-solvent fluorinated electrolyte with a special solvation sheath of Li^(+),which can prevent the formation of dissoluble long-chain LiPS of the sulfur cathode,restrict Li dendrite growth at the anode side,and show fire resistance in combustion experiments.As a result,the proposed Li-S batteries with 70 wt%sulfur content in its cathode deliver stable life cycle,low self-discharge ratio,and intrinsic safety.Therefore,the unique passivation characteristics of the designed fluorinated electrolyte break several critical limitations of the traditional“liquid phase”-based Li-S batteries,offering a facile and promising way to develop long-life and high-safety Li-S batteries.