Non-desolvation Zn^(2+)storage mechanism enables MoS_(2)anode with enhanced interfacial charge-transfer kinetics for low temperature zinc-ion batteries

摘要

The emerging rocking-chair aqueous zinc-ion battery(AZIB)configuration provides a promising approach for realizing their practical applications by avoiding the critical drawbacks of Zn metal anodes including unsatisfactory Coulombic efficiency and low Zn utilization.Therefore,exploiting appropriate insertion-type anodes with fast charge-transfer kinetics is of great importance,and many modifications focusing on the improvement of electron transport and bulk Zn^(2+)diffusion have been proposed.However,the interfacial Zn^(2+)transfer determined by the desolvation process actually dominates the kinetics of overall battery reactions,which is mainly overlooked.Herein,the interlayer structure of Mo S_(2)is rationally co-intercalated with water and ethylene glycol(EG)molecules(Mo S2@EG),giving rise to a fast non-desolvation Zn^(2+)storage mechanism,which is verified by the extraordinarily smaller activation energy of interfacial Zn^(2+)transfer(4.66 k J mol^(-1))compared with that of pristine Mo S_(2)(56.78 k J mol^(-1)).Furthermore,the results of theoretical calculations,in-situ Raman and ex-situ characterizations also indicate the enhanced structural integrity of Mo S2@EG during cycling due to the enlarged interlayer spacing and charge screening effect induced by interlaminar EG molecules.Consequently,the Mo S_(2)@EG anode enables excellent cycling stability of both high-energy-density Mo_S2@EG||PVO(polyaniline intercalated V_(2)O_(5))and high-voltage Mo S2@EG||Na_(3)V_(2)(PO_(4))_2O_(2)F(NVPF)full batteries with neglectable capacity decay at-20℃.