基于动力学匹配原则构筑高性能锂离子电容器

High performance lithium-ion capacitors based on dynamic matching principle

锂离子电容器作为新一代电化学储能系统,结合高能量和高功率密度的优势,满足多功能电子设备和电网侧储能的迫切需求。然而,电池型负极和电容型正极之间的动力学不匹配严重制约了其电化学性能。为解决这一瓶颈,制备一种高性能双碳锂离子电容器,该器件采用乙二胺四乙酸铁钠盐(EDTA-Na-Fe)衍生而成的碳材料同时作为正、负极。通过简单的煅烧,EDTA-Na-Fe可直接转化为氮掺杂碳骨架(NCF),该碳骨架具有较高的可逆容量和良好的电化学性能。使用NCF同时作为锂离子电容器的正、负极,能够在0.5~4.0 V的电压区间工作,并且由于使用同样的正负极材料,简化器件的构筑流程;在225 W·kg^(-1)的功率密度下,所构筑器件的能量密度能达到193.4 Wh·kg^(-1)。这种合理的动力学匹配策略为进一步发展高性能锂离子电容器开辟一条新的途径。

As a new generation of energy storage devices,lithium-ion capacitors(LICs)rationally combine high energy density and high power density,providing an alternative solution for multi-functional electronic equipment and state grid system.However,the dynamic mismatch between the battery-type anode and the capacitor-type cathode seriously limits its development and application.Herein,a high performance LIC simultaneously using carbon materials derived from Ethylenediaminetetraacetic Acid Ferric Sodium Salt(EDTA-Na-Fe)was prepared.By calcination of EDTA-Na-Fe in an inert atmosphere,nitrogen-doped carbon frameworks(NCF)can be obtained which possess a high reversible capacity and excellent rate-capability.Using this NCF as the anode and cathode of the LICs,the hybrid devices with a wide voltage window of 0.5-4.0 V are obtained.The employment of the same materials as the anode and cathode can largely simplify the fabrication process.The energy density of LICs can reach 193.4 Wh·kg^(-1)at a power density of 225 W·kg^(-1).This reasonable dynamic matching strategy can be helpful for the application of LICs.