3D artificial electron and ion conductive pathway enabled by MgH2 nanoparticles supported on g-C3N4 towards dendrite-free Li metal anode

Abstract

Li metal anode is considered as one of the most promising candidates for next-generation batteries due to its high energy density. The undesired growth of Li dendrites and infinite volume change, however, hinders its practical application. Herein, a 3D structured Li metal anode featured with uniform electron and Li ion conductive pathway is fabricated through the favorable reaction between MgH2 that are uniformly distributed on g-C3N4 and molten Li. The thus-formed lithiophilic LiMg alloys under the structural support of lithiophilc g-C3N4 could synergistically lower the nucleation barrier of Li plating and hence promote the uniform Li deposition process. Simultaneously, the high Li ion conductivity of thus-formed both LiH and Li3N resulting from the reaction between molten Li and MgH2 and g-C3N4, respectively, facilitates fast Li ion transportation kinetics along their surfaces towards favorable Li deposition on the surface of g-C3N4. Consequently, the thus-fabricated Li metal anode with a high specific capacity of 3511 mA h g − 1 delivers a long cycling life of over 500 h at 3 mA cm−2 under 3 mA h cm−2. Impressively, upon coupling this anode with commercial LFP cathode, the thus-assembled full cells deliver a specific capacity of 145 mA h g − 1 after 450 cycles at 1 C.