Enhanced Cycling Performance of Magnesium‐Doped Lithium Cobalt Phosphate

Abstract

The cycling performance of LiCoPO4 (LCP) as a high voltage positive electrode material in lithium‐ion batteries is enhanced by partial magnesium substitution for cobalt. Structural investigation of magnesium‐doped LCP using combined powder neutron and X‐ray diffraction reveals a decrease in anti‐site defects. In addition, the reduced unit cell volume variation during the charging process is observed by operando X‐ray diffraction measurements. Characterisation of the surface shows the presence of a Mg‐rich layer on the surface that might prevent detrimental reactions with the electrolyte. The combined beneficial effects of magnesium doping in LCP result in improved capacity retention.

One-Step Synthesis of LiCo1-1.5xYxPO4@C Cathode Material for High-Energy Lithium-ion Batteries

“…Lots of work have been undertaken to solve these problems, including decreasing the cathode particle size and controlling the morphology to shorten the Li-ion migration distance [ 21 , 22 , 23 , 24 ]; coating the cathode particle with stable materials [ 25 , 26 , 27 , 28 ] or conductive materials [ 29 , 30 , 31 , 32 , 33 ] to stabilize the interface and reduce the side reaction; partial substitution at Co site [ 20 , 34 , 35 , 36 , 37 ] to improve the intrinsic ionic and electronic conductivity [ 34 , 35 , 38 , 39 , 40 ]; and adding electrolyte additives to suppress the electrolyte decomposition [ 14 , 41 , 42 ]. Every method has some effect in improving LiCoPO 4 cathode performance.…”

“…Every method has some effect in improving LiCoPO 4 cathode performance. Generally, for LiCoPO 4 cathode material, surface coating is the most effective way to enhance the stability of the interface [ 25 , 31 , 43 ], while cation substitution can significantly improve the material ionic conductivity [ 16 , 36 , 44 , 45 ].…”

Thermally Labile Organic-Soluble Heterometal Diorganophosphate-Derived Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…57,71 The diffraction pattern obtained at 700 °C matches well with the reported ICSD:14847 pattern, and the FT-IR spectrum peaks are also in correspondence with Pnma-LiCoPO 4 (Figure S13). 76 Valence State Analysis. The surface elemental composition and valence states of Li-Co-P-HEX and Li-Co-P-BT were investigated by XPS analysis.…”

Atomic Layer Fluorination of 5 V Class Positive Electrode Material LiCoPO4 for Enhanced Electrochemical Performance

“…[10] However, practical implementation of LCP technology has been hampered by its unsatisfactory electrochemical performance associated with poor cycling stability and low rate capability, mainly due to the formation of undesired products on the surface of LCP, [11] following the structural degradation of LCP by HF present in the electrolyte [12] as well as the increase in the number of anti-site defects. [13,14] Over the years, many efforts have been made to mitigate these problems, such as metal doping [15] in the LCP crystal structure, surface coating [16] and nanostructuring. [17] In addition, the use of additives in the electrolyte, [18,19] the modification of separator [20] and the use of water soluble binders [21] have proved to be effective.…”