A lithiophilic AlN-modified copper layer for high-performance lithium metal anodes

Metallic lithium is believed to be the next generation anode material for high energy density energy storage devices due to its high theoretical specific energy density and low electrochemical potential. However, the practical application of lithium metal anodes is impeded by their unstable electrode interface and lithium dendrite formation. Herein, constructing an AlN protection layer on the lithium metal interface by a facile blade casting method is reported to inhibit the growth of lithium dendrites. Via the spontaneous reactions, the in situ formed ionically super conductive Li₃N and lithiophilic Li-Al alloy reduce the lithium diffusion barrier and enhance the lithium transfer kinetics synergistically, guiding uniform Li deposition without lithium dendrites. The symmetric Li/Li cell sustains 1300 h at 1 mA cm⁻² and 1 mA h cm⁻² with a remarkable low voltage hysteresis of about 10 mV. The feasibility of the AlN layer protected anode is confirmed in conjunction with LiFePO₄ cathodes. The full cells based on the LiFePO₄ cathode deliver an exceptionally high capacity retention of 96.3% after 200 cycles at 1C at a critical restricting N/P capacity of 1.2. In addition, this modified layer is also valid for Li/S batteries. This method provides a great promise for the commercialization of Li metal batteries.