Composite powder for use in an anode of a lithium ion battery, method of preparing such a composite powder and method for analysing such a composite powder

A composite powder for use in an anode of a lithium ion battery, wherein particles of the composite powder comprise silicon-based domains in a matrix, and wherein the matrix comprises carbon or a precursor material that can be converted into carbon by thermal treatment, and wherein the individual silicon-based domains are either:

• free silicon-based domains that are not or not completely embedded in the matrix, or
• fully embedded silicon-based domains that are completely surrounded by the matrix,
• wherein the percentage of free silicon-based domains is lower than or equal to 4 weight % of the total amount of Si in metallic or oxidized state in the composite powder, and
• wherein the silicon-based domains have a weight based size distribution with a d50 of 200 nm or less and a d90 of 1000 nm or less, and wherein the composite powder also comprises graphite, wherein the graphite is not embedded in the matrix.