Effect of lithium-containing inorganic phosphate additives in stabilization of carbonate-based electrolyte for 5 V LiNi0.5Mn1.5O4-based lithium-ion batteries

High-voltage lithium-ion batteries (LIBs) with LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode are considered promising energy sources due to their high energy density . However, enhancing the stability of the electrode/electrolyte interface remains critical for the practical application of LIBs. In this work, lithium-containing inorganic phosphates (LiPO 3 , Li 3 PO 4 , and LiH 2 PO 4 ) were used as multifunctional inorganic additives to improve the stability of the electrode/electrolyte interface in 5.0 V, LNMO-based LIBs with carbonate-based electrolytes. Based on theoretical calculations and experimental evaluations of the electrochemical performance , LiPO 3 was selected as the optimal additive for further study in LNMO/Li and LNMO/Li 4 Ti 5 O 12 cells. The LNMO/Li half-cells with LiPO 3 delivered an initial discharge capacity of 108.8 mAh∙g −1 and retained a capacity of 94.9 % after 500 cycles at 5C, compared to 75.1 mAh∙g −1 and 79.4 % for the standard electrolyte. The increased cycling stability was ascribed to the ability of the multifunctional, film-forming LiPO 3 additive to form stable interfacial films on both the cathode and anode , thus, inhibiting side reactions between the electrodes and electrolyte. Moreover, as an HF scavenger, LiPO 3 reduced the HF content in the electrolyte to ensure the structural integrity of LNMO and inhibit the dissolution of transition metal ions . In the LNMO/Li 4 Ti 5 O 12 full cells, the addition of LiPO 3 effectively enhanced the cycling performance, and the capacity retention after 400 cycles at 5C was 79.1 %, compared to only 12.3 % for the standard electrolyte. Considering its simplicity, low cost, and feasibility, the addition of LiPO 3 as a multifunctional electrolyte additive showed excellent prospects for commercial applications.