Non-aqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery, comprising:

• a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein
• the negative electrode has a negative electrode current collector, and a negative electrode mixture layer formed on a surface of the negative electrode current collector,
• the negative electrode mixture layer contains a negative electrode active material including at least a Si-containing material,
• the Si-containing material includes a first composite material having a carbon phase and silicon phases dispersed in the carbon phase,
• an intra-particle porosity of the first composite material is 6% or more and 20% or less,
• the negative electrode mixture layer has a first region and a second region, the first region being nearer to the negative electrode current collector than the second region, and
• an inter-particle porosity S1 in the first region and an inter-particle porosity S2 in the second region satisfy
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• %
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• and
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• 1.