▎ 摘　　要

NOVELTY - A lubricating oil additive comprises 0.01-0.9 %mass surface-treated graphene containing bile acid salt or its derivative. USE - The lubricating oil additive is useful in lubricating oil (claimed). ADVANTAGE - The lubricating oil additive: has excellent dispersibility; can be prepared in a simple manner with high yield; and can effectively increase the anti-friction properties of lubricating oil and reduce the loss of engine. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for lubricating oil, which comprises lubricating oil additive.