Energy density maximization of Li-ion capacitor using highly porous activated carbon cathode and micrometer-sized Si anode
Energy density maximization of Li-ion capacitor using highly porous activated carbon cathode and micrometer-sized Si anode
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DOI：
10.1016/j.electacta.2021.139115
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发表时间：
2021-08-26
影响因子：
6.6
通讯作者：
Kumagai, Seiji
中科院分区：
文献类型：
--
作者：
Eguchi, Takuya;Sawada, Keiichiro;Kumagai, Seiji
采用市售活性炭（AC）和常规的2 μ m大小的Si分别作为正极和负极材料，在AC:Si质量比为6.37的条件下，开发了一种非常高能量密度的锂离子电容器（LIC）。在功率密度为32 W kg（-1）时，LIC提供了400 Wh kg（-1）的最大能量密度，并在1.0-4.3 V的电池电压范围内表现出优异的速率稳定性（在6 kW kg（-1）时200 Wh kg(-1)）；这些数值是基于阴极（AC）和阳极（Si）中活性物质的总质量。然而，其较低的循环稳定性导致其能量密度下降79.9%(278至56 Wh kg(-1))，在类似于650 W kg（-1）的情况下循环10 0 0次。研究了阴极和阳极在充放电循环过程中的电位变化。事后电极分析表明，阳极允许Si颗粒分层，形成以LiF为主的厚的60 nm的钝化固体电解质间相层。将电池电压范围降至2.0-4.0 V，质量比降至3.30，能量密度降至183 Wh kg(-1)，但提高了可持续性（176至156 Wh kg(-1)，保留率为88.6%），并在2000次类似于1 kW kg（-1）的循环后保持功率密度(> 10 kW kg（-1), 100 Wh kg(-1)）。(C) 2021 Elsevier Ltd版权所有。
A very-high-energy-density Li-ion capacitor (LIC) was developed using commercially available activated carbon (AC) having a high surface area of 3041 m 2 g(-1) and conventional 2 mu m-sized Si as the cathode and anode material, respectively, at an AC:Si mass ratio of 6.37. The LIC delivered a maximum energy density of 400 Wh kg(-1) at a power density of 32 W kg(-1) and exhibited excellent rate stability (200 Wh kg(-1) at 6 kW kg(-1)) over the cell voltage range of 1.0-4.3 V; these values were based on the total mass of the active materials in the cathode (AC) and anode (Si). However, its low cycling stability induced a 79.9% decrease in its energy density (278 to 56 Wh kg(-1)) following 10 0 0 cycles at similar to 650 W kg(-1). The potential variations of the cathode and anode were investigated during charge/discharge cycling. Postmortem electrode analyses indicated that the anode permitted the delamination of Si particles and the formation of a thick passive solid electrolyte interphase layer (60 nm) mainly constituted of LiF. Reducing the cell voltage range to 2.0-4.0 V and the mass ratio to 3.30 reduced the energy density to 183 Wh kg(-1) but improved the sustainability (176 to 156 Wh kg(-1), 88.6% retention) and maintained the power density (> 10 kW kg(-1) at 100 Wh kg(-1)) following 2000 cycles at similar to 1 kW kg(-1). (C) 2021 Elsevier Ltd. All rights reserved.