How to improve the efficiency of liquid-phase shear exfoliation (LPSE) for mass production of large-size graphene nanosheets still remains an ongoing challenge. In this work, we have developed a LPSE method using a rotor-stator mixer. It is quite simple and efficient by exfoliation of expanded graphite (EG) in N-methyl-2-pyrrolidone (NMP) with the assistance of organic salts including sodium citrate, potassium citrate and sodium tartrate. The LPSE of EG in NMP can provide improved yields, up to 6 times as high as values from exfoliation of natural flake graphite (NFG). The additive of organic salts in NMP can make a further improvement in graphene yields, 1.5 times higher than that obtained only in NMP. Remarkably, the yields of the as-exfoliated graphene are as high as 10% under optimal conditions, and up to 50% after multiple-cycle exfoliation. Organic salts in LPSE act as analogue grinding aids enhancing the applied shear forces and thus contributing to the improved efficiency of LPSE, but they do not intercalate into the interplanar spaces of graphite. This facile LPSE method should have excellent potential in the large scale production of graphene nanosheets for numerous applications.

如何提高液相剪切剥离 (LPSE) 的效率以大规模生产大尺寸石墨烯纳米片仍然是一个持续的挑战。在这项工作中，我们开发了一种使用转子 - 定子混合器的 LPSE 方法。通过在包括柠檬酸钠、柠檬酸钾和酒石酸钠在内的有机盐的帮助下，在 N-甲基-2-吡咯烷酮 (NMP) 中剥离膨胀石墨 (EG)，这是非常简单和有效的。NMP 中 EG 的 LPSE 可以提供更高的产量，最高可达天然鳞片石墨 (NFG) 剥离值的 6 倍。NMP中有机盐的添加可以进一步提高石墨烯的产率，比仅在NMP中获得的产量高1.5倍。值得注意的是，剥离后的石墨烯在最佳条件下的产率高达 10%，在多次循环剥离后高达 50%。LPSE 中的有机盐可作为类似的研磨助剂，增强所施加的剪切力，从而有助于提高 LPSE 的效率，但它们不会嵌入石墨的晶面空间中。这种简便的 LPSE 方法在石墨烯纳米片的大规模生产中具有出色的潜力，可用于多种应用。