Stabilizing the Electrode/Electrolyte Interface of LiNi_0.8Co_0.15Al_0.05O₂ through Tailoring Aluminum Distribution in Microspheres as Long-Life, High-Rate, and Safe Cathode for Lithium-Ion Batteries

Abstract

The unstable electrode/electrolyte interface of high-capacity LiNiCoAlO (NCA) cathodes, especially at a highly delithiated state, usually leads to the transformation of layered to spinel and/or rock-salt phases, resulting in drastic capacity fade and poor thermal stability. Herein, the Al-increased and Ni-,Co-decreased electrode surface is fabricated through tailoring element distribution in micrometer-sized spherical NCA secondary particles via coprecipitation and solid-state reactions, aimed at stabilizing the electrode/electrolyte interface during continuous cycles. As expected, it shows much extended cycle life, 93.6% capacity retention within 100 cycles, compared with that of 78.5% for the normal NCA. It also delivers large reversible capacity of about 140 mAh g even at 20 C, corresponding to energy density of around 480 Wh kg, which is enhanced by 45% compared to that of the normal NCA (about 330 Wh kg). Besides, the delayed heat emission temperature and reduced heat generation mean remarkably improved thermal stability. These foregoing improvements are ascribed to the Al-increased spherical secondary particle surface that stabilizes the electrode/electrolyte interface by protecting inner components from directly contacting with electrolyte and suppressing the side reaction on electrode surface between high oxidizing Ni and electrolyte.

Simultaneously Dual Modification of Ni‐Rich Layered Oxide Cathode for High‐Energy Lithium‐Ion Batteries

“…The initial exothermic peaks can be indexed to SEI layer decomposition and there is no significant difference between NCM and LT1. The second exothermic peak is indexed to the cathode decomposition, accompanied by the amount of oxygen generated from the structure of electrode materials . The NCM sample exhibits a broad exothermal peak around 228.58 °C with a heat generation of 1141 J g −1 , while the LT1 sample shifts to a higher temperature (243.97 °C) and overall heat generation was reduced to 655.8 J g −1 .…”

30 Years of Lithium‐Ion Batteries

“…Copyright 2007, Electrochemical Society, Inc. f) Thermal stability of regular NCA and modified NCA (Ni:Co:Al = 0.8:0.15:0.05). Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…This phenomenon decayed the cathode and had very recently led material scientists to apply more resistive coatings composed of ZnO, FePO 4 , Li 3 PO 4 , AlPO 4 , LiMnPO 4 among many other similar concepts from work done on surface coatings for NMC. Al offered good thermal stability compared to LCO and LNO but still underwent severe exothermic reactions at higher temperatures (200–250 °C) when NCA was at its delithiated state . The thermal stability of NCA was inferior to NMC 333 due to the higher Ni content which rendered it problematic for commercial use.…”

Enhanced Electrochemical and Thermal Stabilities of Li[Ni0.88Co0.09Al0.03]O2 Cathode Material by La4NiLiO8 Coating for Li–Ion Batteries

“…However, insufficient energy density due to the limited lithium utilization (<60 %) in the structure of LCO, as well as the high cost of cobalt, restricts its broad applications in stationary energy storage and electric vehicles (EVs) . Hence, intensive researches have been implemented, which focus on developing alternative cathode materials with higher lithium utilization and larger energy density, to expand the application field of LIBs . Furthermore, LIBs for grid‐level energy storage and EVs are expected to offer low cost, superior safety and fast charging .…”

“…and spinel oxides LiM 2 O 4 (M=Mn, Ni and Co), together with olivine phosphates LiMPO 4 (M=Fe, Ni, Co and Mn) are three categories main cathode materials for lithium ion batteries . Among these alternatives, Ni‐rich layered oxides of Ni−Co−Mn (NMC) and Ni−Co−Al (NCA) are considered as the promising cathode materials for next‐generation LIBs because of their relatively high reversible capacities (∼200 mAh g −1 ) . Nevertheless, high Ni content results in the inferior structural stability of the oxides.…”