Hybrid electrolytes with an ultrahigh Li-ion transference number for lithium-metal batteries with fast and stable charge/discharge capability

Electrolytes with a high ionic transference number hold great promise for reducing battery polarization and achieving safe energy storage. Herein, single-ion electrolytes containing alpha-LiAlO2@gamma-Al2O3 nanosheets as fillers in PVDF-HFP are prepared. The alpha-LiAlO2@gamma-Al2O3 nanosheets show excellent anion-anchoring ability due to the high adsorption energy to anions on the surfaces, leading to a remarkable lithium-ion (Li+) transference number of 0.92 and a great ionic conductivity of 0.85 mS cm(-1) at room temperature. Such a high Li+ transference number effectively alleviates the concentration gradient polarization, improves the homogeneous Li+ deposition, and suppresses the Li dendrite growth. As a result, the symmetric Li||Li cell realizes superior interfacial stability and dendrite suppression capability for 1000 h at a current density of 0.5 mA cm(-2). Moreover, the LiNi0.85Co0.05Al0.1O2||Li and LiFePO4||Li batteries with the electrolyte demonstrate significantly improved specific capacities and excellent cycling durabilities at high rates. Especially, the LiFePO4||Li battery exhibits a capacity retention of 88% over 2000 charge/discharge cycles at a rate of 2C. This work offers a strategy for designing single-ion electrolytes toward high-performance energy storage.