Coating Solution for High-Voltage Cathode: AlF₃ Atomic Layer Deposition for Freestanding LiCoO₂ Electrodes with High Energy Density and Excellent Flexibility

Abstract

Freestanding LiCoO/multiwall carbon nanotube/nanocellulose fibril (LCO-MWCNT-NCF) electrodes are fabricated by a vacuum filtration technique. The electrode has a high LCO loading of 20 mg/cm with excellent flexibility, uniform material distribution, and low surface resistivity. When coated with 2 ALD cycles of AlF, LCO-MWCNT-NCF has a high specific capacity of 216 mAh/g at 4.7 V. The freestanding AlF-coated electrode preserves 75.7% of its initial capacity after 100 cycles and 70% after 160 cycles of charge discharge. In contrast, electrodes coated with 2 ALD cycles of AlO cannot be cycled above 4.5 V. By elimination of the unnecessary weight of current collector, and increasing in the working voltage simultaneously, this freestanding LCO-MWCNT-NCF electrode can significantly improve the gravimetric and volumetric energy density of lithium ion batteries.

Recent Progresses and Development of Advanced Atomic Layer Deposition towards High-Performance Li-Ion Batteries

“…As for coating approaches, the ALD, in sharp comparison with the conventional mechanical mixing and sol-gel methods, affords extraordinary homogeneous cladding layer on the surface with precisely regulated down to sub-nanometers levels [ 5 , 164 ]. In this part, we comprehensively summarize the surface engineering via the ALD for cathode materials including layered cathodes, such as LiCoO 2 [ 111 , 112 , 118 , 148 , 149 ], LiNi x Mn y Co z O 2 [ 113 , 114 , 119 , 154 , 155 , 156 , 157 ], and Li-rich x Li 2 MnO 3 ·(1 − x )LiMO 2 (M = Mn, Ni, Co) [ 161 , 162 , 163 ], and spinel cathodes, such as LiMn 2 O 4 [ 150 , 151 , 152 , 153 ] and LiNi 0.5 Mn 1.5 O 4 [ 52 , 158 , 159 , 160 ], as listed in Table 3 . After careful observation in Table 3 , we can discover that the compounds serving as ALD coating layer for cathode materials can be mainly divided into four categories: metal oxides (Al 2 O 3 [ 118 , 119 , 152 , 154 , 155 , 156 , 159 , 161 , 163 , 165 , 166 ], TiO 2 ...…”

Nanocellulose, a Versatile Green Platform: From Biosources to Materials and Their Applications

“…By introducing polyaniline into a reduced graphene oxide (RGO)/nanocellulose composite enhanced both thermal stability and conductivity. Microscopic evaluation of the ternary composites shows that PANi nanoparticles formed a spherical shape over the RGO/NC template, which in turn increased the thermal stability of the composite434 .A LiCoO 2 /multiwall carbon nanotube/NCF paper was produced with a higher energy density than other currently reported freestanding electrodes, thus such a composite is enticing as a flexible battery435 . The lightweight, low volume composite was fabricated by mixing the LiCoO 2 , carbon nanotubes and NCF in solution and casting a membrane.…”

Applications of Nanocellulose/Nanocarbon Composites: Focus on Biotechnology and Medicine

“…Electrospun core-shell nanofibrous membranes, containing CNTs stabilized with cellulose nanocrystals, were developed for use as high-performance flexible supercapacitor electrodes with enhanced water resistance, thermal stability and mechanical toughness [40]. Electrodes for lithium batteries were based on freestanding LiCoO 2 /MWCNT/cellulose nanofibril composites, fabricated by a vacuum filtration technique [148], or on freestanding CNT-nanocrystalline cellulose composite films [41]. Thermoelectric generators for heat-to-electricity conversion were based on large-area bacterial nanocellulose films with an embedded/dispersed CNT percolation network, incorporated into the films during nanocellulose production by bacteria in culture [57].…”