Negative electrode active material, secondary battery, and method for producing artificial graphite particles
AssigneePrime Planet Energy & Solutions, Inc.
InventorShuhei Takeshita
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Abstract
A negative electrode active material capable of suppressing expansion of a negative electrode is provided. The negative electrode active material disclosed herein includes artificial graphite particles having a plurality of internal voids. The artificial graphite particles have a porosity of 0.7 to 15%. When binarization is performed on a cross-sectional electron microscopic image of 10 or more of the artificial graphite particles arbitrarily selected, circular approximation is then performed on internal voids having cross-sectional areas of 1000 nm2 or more, and circularities of 20 or more of the internal voids arbitrarily selected in each particle are determined, the internal voids have an average circularity of 0.1 to 0.6.
Claims7
A negative electrode active material comprising:
- artificial graphite particles, wherein
- the artificial graphite particles are primary particles each having a plurality of internal voids
- the artificial graphite particles have a porosity of 0.7 to 15%, and
- when binarization is performed on a cross-sectional electron microscopic image of 10 or more of the artificial graphite particles arbitrarily selected, circular approximation is then performed on internal voids having cross-sectional areas of 1000 nm2 or more, and circularities of 20 or more of the internal voids arbitrarily selected in each particle are determined, the internal voids have an average circularity of 0.1 to 0.6.
Dependencies are inferred from the claim text.