Enhancing the reversible capacity and cycle stability of lithium-ion batteries with Li-compensation material Li6CoO4

Abstract

High-capacity anode materials, such as SiO and Si/C, are considered promising candidates for high-energydensity lithium-ion batteries. However, the low initial Coulombic efficiency of these anode materials induced by side reactions (forming Li 2 O and lithium silicate) and the formation of solid electrolyte interface film reduces the active Liions and causes low-discharge capacity. Adding a Li-compensation material in the cathode or anode is an effective strategy to overcome this problem. The most used Li-compensation material is the stabilized lithium metal powder. However, this strategy has high safety risks, high costs, and is challenging to quantify. Herein, the Li-compensation material of Li 6 CoO 4 is synthesized and investigated. The preparation conditions, stability in the air, delithiation mechanism, and structural transformation are analyzed and discussed. Electrochemical tests reveal that the discharge capacity and capacity retention of the full pouch cells (3-Ah) with Li 6 CoO 4 additive is significantly improved. Also, the reason for such improvement is investigated. This work provides an effective strategy of Li-compensating technology to enhance the electrochemical performance of lithium-ion batteries.

Advancements in Prelithiation Technology: Transforming Batteries from Li‐Shortage to Li‐Rich Systems

“…Moreover, Li 6 CoO 4 could remain structurally, morphologically, and electrochemically stable for 1 h when exposed to a relative humidity (RH) of 50%. [ 86 ] Thus, Li et al. successfully prepared air‐stable Li 6 CoO 4 @Li 5 FeO 4 (LCO@LFO) composite prelithiation reagents by delicately encapsulating Li 5 FeO 4 with Li 6 CoO 4 (Figure 8f).…”

“…Moreover, Li 6 CoO 4 could remain structurally, mor-phologically, and electrochemically stable for 1 h when exposed to a relative humidity (RH) of 50%. [86] Thus, Li et al successfully prepared air-stable Li 6 CoO 4 @Li 5 FeO 4 (LCO@LFO) composite prelithiation reagents by delicately encapsulating Li 5 FeO 4 with Li 6 CoO 4 (Figure 8f). Ultimately, Li 6 CoO 4 @Li 5 FeO 4 showed exceptional resistance to water and oxygen and was stable in air for 1 h. [87] However, Co is relatively expensive, so particular attention needs to be paid to the application costs of Li 6 CoO 4 .…”

“…f) Schematic illustration of the preparation of Li 6 CoO 4 @Li 5 FeO 4 . Reproduced with permission [86]. Copyright 2021, IOP Science.…”

Li2CO3 Nanocomposites as Cathode Lithium Replenishment Material for High-Energy-Density Li-Ion Batteries

“…However, they are unstable in the atmosphere, and when lithium ions are released, they generate enormous amounts of gas or produce residual substances that are detrimental to the battery, which can significantly impair the electrochemical performance of lithium-ion batteries. , Besides, the mixture of lithium-containing small molecules and transition-metal-containing materials (e.g., Co and CoO) can also achieve the effect of lithium replenishment. ,, However, the products contain inactive Co 3 O 4 residues, which deteriorate the battery cycling life. In addition, lithium salts of metal oxides like Li 6 CoO 4 , , Li 5 FeO 4 , and Li 2 NiO 2 are not stable in the air and can provide limited active lithium ions, hindering the actual application. Recently, organic lithium salts, such as Li 2 C 2 O 4 , have also been found to be useful as lithium replenishment material. − Despite being stable in air and not repelling the battery system, they have a relatively low irreversible capacity and require more volume to refill the lithium, which has an impact on the energy density of lithium-ion batteries.…”

“…19,25,26 However, the products contain inactive Co 3 O 4 residues, which deteriorate the battery cycling life. In addition, lithium salts of metal oxides like Li 6 CoO 4 , 27,28 Li 5 FeO 4 , 29 and Li 2 NiO 2 30 are not stable in the air and can provide limited active lithium ions, hindering the actual application. Recently, organic lithium salts, such as Li 2 C 2 O 4 , have also been found to be useful as lithium replenishment material.…”