Improvements in methods for measuring the volume conductivity of electrically conductive carbon powders
Improvements in methods for measuring the volume conductivity of electrically conductive carbon powders
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DOI：
10.1016/j.apt.2021.01.016
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发表时间：
2021-03-05
影响因子：
5.2
通讯作者：
Ryan, Cecily
中科院分区：
文献类型：
--
作者：
Kane, Seth;Warnat, Stephan;Ryan, Cecily
导电碳粉通常用作聚合物中的填充材料，用于制造用于电池电极和防静电应用的半导体导电复合材料。目前表征这些粉末导电性的方法使用两个活塞来压缩粉末。众所周知，双活塞方法低估了电导率。本研究开发了一种基于ASTM D257的保护电极法，以更好地表征导电粉末的体电导率和阻抗频谱。用高导电性粉末(铜粉)和低导电性粉末(纤维素)的导电性和阻抗谱来约束炭黑、石墨和生物炭的导电性。用双活塞和保护电极法对粉末进行了全范围压缩测量。在所有情况下，使用保护电极法测量的粉末比使用双活塞方法测量的相同粉末具有更高的导电性和更低的阻抗。利用GEM方程对颗粒电导率与堆积分数的关系进行了拟合，得到了颗粒电导率。保护电极法比双活塞法更接近通过铜和石墨的四探针法测得的既定电导值。(C)2021年日本粉末技术学会。由Elsevier B.V.和日本粉末技术学会出版。版权所有。
Electrically conductive carbon powders are commonly used as filler materials in polymers to create elec-trically semi-conductive composite materials for use in battery electrodes and anti-static applications. Current methods for characterizing the conductivity of these powders use two pistons to compress the powders. Two-piston methods are known to underestimate conductivity. This study develops a guard-electrode method based on ASTM D257 to better characterize the bulk conductivity and impedance spec-tra of electrically conductive powders. The conductivity and impedance spectra of a highly conductive powder (copper powder) and a low conductivity powder (cellulose) were used to bound the conductivity of carbon black, graphite, and biochar. Powders were measured through a full range of compression with both the two-piston and the guard-electrode method. In all cases, measurements using the guard-electrode method have higher conductivity and lower impedance than the same powders measured using the two-piston method. The grain conductivity of the particles is obtained through fitting the relationship of conductivity versus packing fraction using the GEM equation. The guard-electrode method is shown to be more similar to established conductivity values as measured via a four-probe technique for copper and graphite then the two-piston method.(c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.