NONAQUEOUS SECONDARY BATTERY BILAYER STRUCTURE CARBON MATERIAL AND NONAQUEOUS SECONDARY BATTERY ANODE AND NONAQUEOUS SECONDARY BATTERY USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery carbon material which can achieve high capacity even when rolled with such a degree of pressure that does not cause material breakdown and can restrain charge/discharge irreversible capacity.SOLUTION: A nonaqueous secondary battery bilayer structure carbon material is provided, in which at least part of the surfaces of graphite particles are covered with carbonaceous matter, characterized in that the following conditions (1) to (3) are satisfied: (1) The average grain size d50 of the bilayer structure carbon material 19.1 μm to 50 μm, both ends incl.; (2) The circularity of the bilayer structure carbon material is 0.88 or more; (3) a ratio (P/d50) of a rolling load (P) defined below to d50 of the bilayer structure carbon material is 30 or less. P=linear pressure (kg/5 cm) necessary to roll an anode active material layer under a specific condition using the bilayer structure carbon material.