Improved Lithium-Ion Transport Within the LiNi_0.8Co_0.15Al_0.05O₂ Secondary Cathode Particles Through a Template-Assisted Synthesis Route

Abstract

Herein, we report a sacrificial carbon fiber (CF) template-assisted synthesis of LiNi0.8Co0.15Al0.05O2 (C-NCA) by the Pechini method. An anisotropic primary particle morphology with an interconnected microstructure is obtained, originating from local overheating and oxygen-deficient zones induced by combustion of the CFs during high-temperature lithiation. Moreover, the particles assembled around the CFs demonstrated denser packing compared to the reference bare NCA (B-NCA) synthetized in the absence of the CF template. The anisotropic surfaces facilitate ion transport and stabilize the structure for high voltage and temperature operation. C-NCA||Li metal cells exhibit a reversible capacity of 106 mA h g–1 at 10 C and are able to retain 96% of their initial capacity as the C-rate is reverted to 0.1 C. The state of health of C-NCA||graphite full cells remains at 70% after 200 cycles at 0.33 C within 2.8–4.3 V. The results outperform the B-NCA cell, exhibiting a significant loss over 66 cycles while delivering only 50% of its initial capacity. The synthesis method allows for a straightforward route for tailoring the particle size, shape, and crystallinity, enabling the development of stable nickel-rich cathode materials, even at an upper cutoff voltage of 4.5 V or an operating temperature of 60 °C.

Practical Implementation of Magnetite-Based Conversion-Type Negative Electrodes via Electrochemical Prelithiation

“…The extent of the parasitic reactions within the cells is displayed by the integration of the capacity losses over extended cycling by representing the sum of the Coulombic inefficiencies during the long-term cycling, namely as accumulated Coulombic inefficiencies (ACIE) Figure a demonstrates that the slope of the ACIE of the non-prelithiated cell is significantly steeper compared to prelithiated cells, indicating that the surface decomposition and film formation reactions of the non-prelithiated Fe 3 O 4 @PrGO electrode were progressive, even beyond 100 cycles of operation . The FeGO electrode surface area was found to be continuously increasing by breaking and reorganization of broken Fe 3 O 4 particles in the GO-based matrix .…”

“…19 Figure 6a demonstrates that the slope of the ACIE of the non-prelithiated cell is significantly steeper compared to prelithiated cells, indicating that the surface decomposition and film formation reactions of the nonprelithiated Fe 3 O 4 @PrGO electrode were progressive, even beyond 100 cycles of operation. 39 The FeGO electrode surface area was found to be continuously increasing by breaking and reorganization of broken Fe 3 O 4 particles in the GO-based matrix. 26 In full cells, such situation consumes the initially limited Li + ions from the positive electrode, resulting in higher ACIEs.…”

“…The synthesis of the negative electrode active material, magnetite-decorated partially reduced graphene oxide (PrGO) aerogel, was conducted as reported in our previous study. 39 The negative electrode paste was prepared by using a composition of 80 wt % Fe 3 O 4 @PrGO as active material, 10 wt % carbon black (Super C65, Imerys Graphite & Carbon) as conductive agent, and 10 wt % poly(vinylidene difluoride) (PVdF, Solef 5130, Solvay) as binder. First, the PVdF binder was well-dissolved in Nmethyl-2-pyrrolidinone (NMP, anhydrous, purity 99.5%, Sigma-Aldrich).…”

“…26 In full cells, such situation consumes the initially limited Li + ions from the positive electrode, resulting in higher ACIEs. Conversely, the prelithiated cells exhibit much flatter slopes in their ACIE evolution profiles revealing that more moderate surface decomposition reactions were taking place for these cells that resulted in more effective SEI formation 39 or, in other words, a more passivated electrode surface. Although not very extreme, the ACIE of 20% prelithiated cell is slightly higher compared to the 35 and 50% prelithiated cells.…”

A Self‐Standing Flexible Gel Polymer Electrolyte for Dendrite‐Free Lithium‐Metal Batteries

“…Apart from LFP insertion cathode, lithium nickel cobalt aluminium oxide NCA (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) material is also highly sort after because of its high gravimetric energy density. [61] In order to check the versatility of the GPE synthesised, it was assembled against high voltage NCA cathode with lithium metal as anode. Figure S12 shows the initial few cycles of battery cycling.…”