Preparation, Lithium Storage Performance and Thermal Stability of Nickel‐Rich Layered LiNi_0.815Co_0.15Al_0.035O₂/RGO Composites

Abstract

Ni‐rich materials are promising Li‐ion battery cathodes due to their high capacity but still suffer from electrolyte corrosions and inferior thermal stability, limiting the lithium storage capability. To improve both, lithium storage performances and thermal stability, LiNi0.815Co0.15Al0.035O2 (LNCAO)/reduced graphene oxide (RGO) composites are synthesized by chemical lithiation of commercial Ni0.815Co0.15Al0.035(OH)2 precursors with LiOH ⋅ H2O, followed by simply wet coating with RGO. The effects of such RGO modifications on lithium storage performances and thermal stability of the achieved LNCAO/RGO are investigated. Compared to LNCAO, the unique LNCAO/RGO (with ∼2.5 wt.% RGO) electrodes exhibit considerably improved cycling stability and high‐rate capability (a reversible capacity of 135 mAh g−1 at 10 C), with a capacity decay rate of 0.07 % per cycle at 1 C, half of that of pristine LNCAO (0.14 %/cycle). As evidenced by differential scanning calorimetry, thermal stability is also significantly enhanced since the heat generation decreases from 912 to 586 J g−1 for pristine LNCAO and LNCAO/RGO, respectively. This could be ascribed to the unique structures and the encapsulated RGO coating layers, effectively protecting LNCAO against electrolyte corrosions and decreasing the level of Li+/Ni2+ disordering. This study helps us further understand the critical roles of RGO layers in electrochemical performances and thermal stability of Ni‐rich‐based cathodes for lithium/sodium storage.

Synthesis and electrochemical performance of ropelike LiNi0.8Co0.15Al0.05O2 fiber with nano-building blocks

“…R s , R f , R ct, and D are shown in the inset of figure 3(e). D of the NCA fiber was 8.28×10 −10 cm 2 s −1 and higher than that of traditional NCA particles [21,22], indicating the excellent rate capability of the ropelike structure.…”

Insight into the Role of Co and Mn Elements in Ni-Rich LiNi0.9CoxMn0.08–xAl0.02O2 Cathode Materials

“…46,47 However, an appropriate mixture of lithium/nickel is beneficial to the stability of the layered structure due to the "column effect" of Ni 2+ . 48,49 It can be seen from Table 3 that the I (003) /I (104) ratios of NCMA9352, NCMA9532, and NCMA9712 samples are 1.7734, 1.9100, and 1.7813, respectively, all of which are greater than 1.2, indicating that the Li + /Ni 2 mixing degree of all samples is not elevated. 50,51 It can also be seen from Table 3 that the lattice parameter c increases gradually for the NCMA9352, NCMA9532, and NCMA9712 samples, which are 14.1715, 14.1730, and 14.1752 Å, respectively.…”

A Review of Lithium-Ion Battery Fire Suppression

“…LFP has a stable olivine structure and has attracted significant interest [12][13][14][15] due to low cost as it does not contain cobalt, has high average voltage and a low susceptibility to thermal runaway compared to NCM and LCO, providing a good balance between performance and safety [16][17][18]. To date, cathode materials with high capacity and voltage such as nickel- [19][20][21][22][23][24], manganese- [25] and lithium-rich [19,[25][26][27][28][29][30][31] materials, carbon-coated LFP nanospheres [32] and vanadium pentoxide [33] have been recognized. Higher contents of nickel and lithium increase the specific capacity of the cathode material but decrease thermal stability.…”