钠离子电容器MoO_(3)/Mo_(2)CT_(x)负极材料的原位构建及其电化学性能

In-situ construction and electrochemical performance of MoO_(3)/Mo_(2)CT_(x) anode materials for sodium-ion capacitors

钠离子电容器(SIC)兼具超级电容器和可充电电池的双重优势,实现了高能量密度和高功率密度的共存.然而,电池型负极的动力学短板严重阻碍了器件储钠性能的进一步提升.在此,我们提出了一种简单且高效的不完全原位氧化策略,构建了多层堆叠式MoO_(3)/Mo_(2)CT_(x)复合材料,用于SIC的负极.通过对热氧化反应的精准调控,MoO_(3)/Mo_(2)CT_(x)具备了丰富的活性位点、高导电性和结构稳定性,可实现有效储钠.结合以上优势,MoO_(3)/Mo_(2)CT_(x)负极表现出优异的倍率性能和长循环性能.此外,基于MoO_(3)/Mo_(2)CT_(x)负极所构建的SIC在10 kW kg^(−1)下的能量密度为19.4 Wh kg^(−1),在1 A g^(−1)下的5000次循环中的电容衰减仅为21.5%.本文的贡献在于对MoO3基材料的精准设计和优势共建,以推动其实际应用进程.

Sodium-ion capacitors(SICs)combine the advantages of supercapacitors and rechargeable batteries to achieve both high energy density and high power density.However,the slow kinetics of advanced battery-type anode electrodes seriously hinders the further improvement of sodium storage properties.Herein,we propose a simple and efficient incomplete in-situ oxidation strategy to construct multilayered MoO_(3)/Mo_(2)CTx composite as the anode for SIC.Through the precise regulation of thermal oxidation reaction,MoO_(3)/Mo_(2)CTx possesses abundant active sites,high conductivity regime and good structural stability for efficient sodium storage.Based on the above advantages,MoO_(3)/Mo_(2)CTx anodes exhibit excellent rate and long-cycle performance.In addition,the energy density of the SIC constructed based on MoO_(3)/Mo_(2)CTx is 19.4 Wh kg^(−1)at 10 kW kg^(−1),and the capacitance decay is only 21.5%in 5000 cycles at 1 A g^(−1).The contribution here lies in the precise design and advantageous co-construction of MoO3-based materials to accelerate their practical application.