In the pursuit of higher capacity, rate capability and longer cycling life, other carbon structures have been studied, including fullerenes, carbon nanotubes (CNTs) and graphene, which have zero-, one-, and two-dimensional (2D) architectures, respectively. The carbon atoms in these structures are all sp²-hybridized, the same as those in graphite. Although the Li capacity can be improved greatly upon applying these different morphologies, the nature of the Li-intercalated layer does not change too much among those sp²-hybridized, hexagonal carbon structures, thereby limiting the room for further improvement in capacity. Graphdiyne (GDY) is a new carbon allotrope that was synthesized relatively recently; it comprises sp²- and sp-hybridized carbon atoms and has been predicted to be the most stable of the various diacetylenic non-natural carbon allotropes. Density functional theory and first-principles calculations have indicated that the maximum Li storage capacity of monolayer GDY can be as high as 744 mAh/g (LiC₃), which is twice of the commercial graphite (372 mAh/g, LiC₆). 

A joint research team from Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) and Institute of Chemistry (ICCAS), led by Prof. HUANG Changshui and Prof. LI Yuliang, reported the application of GDY as high efficiency lithium storage materials and elucidated the method of lithium storage in multilayer GDY (Figure 1). Their research results showed that, Lithium-ion batteries featuring GDY-based electrode exhibited excellent electrochemical performance, including high specific capacities, outstanding rate performances, and a long cycle lives. With respect to GDY, its unique structure owning a large number of triangular-like pores, endows GDY more Li storage sites, and facilities Li ions adsorption, desorption and diffusion both in-plane and out-plane. 

It was expected that designing and preparing novel carbon-based materials with large pores will open up new approaches for the development of Li storage materials exhibiting high capacities and excellent cycling stabilities, thereby satisfying the future requirements of next-generation Li storage batteries.