Realizing both high gravimetric and volumetric capacities in Li/3D carbon composite anode

Three-dimensional (3D) current collectors are verified to be highly effective to suppress the dendrite growth and alleviate the volume effect of the secondary Li anode. But this strategy has an intrinsic disadvantage: low practical volumetric capacity density. The main reasons are the limited Li storage space and the low space utilization. Here, a multichannel carbon fiber paper with Au modification on one side (MCNF-Au) is developed as the collector. In this architecture, multichannel structure provides abundant space for Li depositing; the special multichannel geometry generates structural stress which pushes Li-ions to deposit into the inner channels; Au modified on the back side of the matrix enables Li to fill the deep voids between the fibers via heterogeneous nucleation. The latter two guarantee the maximum utilization of the possible spaces. Consequently, the gravimetric and volumetric capacities of Li/MCNF-Au reach 3000 mAh g⁻¹ and 1546 mAh cm⁻³, respectively. When the anode matches with sulfur cathode (20 mg_sulfur cm⁻²), the full cell delivers a high capacity of 1091 mAh g⁻¹ along with good cycle stability at low Li excess (30%). This unique structure provides new inspiration for the volumetric capacity improvement of Li anode.