Leon Shaw; Maziar Ashuri
Abstract
Layered lithium nickel manganese cobalt oxides, Li(NixMnyCoz)O2 where x + y + z = 1 (NMCs), have been studied extensively due to their higher capacity, less toxicity and lower cost compared to LiCoO2. However, widespread market penetration of NMCs as cathodes for Li-ion batteries (LIBs) is impeded by ...
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Layered lithium nickel manganese cobalt oxides, Li(NixMnyCoz)O2 where x + y + z = 1 (NMCs), have been studied extensively due to their higher capacity, less toxicity and lower cost compared to LiCoO2. However, widespread market penetration of NMCs as cathodes for Li-ion batteries (LIBs) is impeded by their poor capacity retention and low rate capability. Coatings provide an effective solution to these problems. This article focuses on review of the recent advancements in coatings of NMCs from the mechanism viewpoint. This is the first time that coatings on NMCs are reviewed based on their functionalities and mechanisms through which the electrochemical properties and performance of NMCs have been improved. To provide a comprehensive understanding of the functions and mechanisms offered by coatings, the following functions and mechanisms are reviewed individually: (i) scavenging HF in the electrolyte, (ii) scavenging water molecules in the electrolyte and thus suppressing HF propagation during charge/discharge cycles, (iii) serving as a buffer layer to minimize HF attack on NMCs and suppress side reactions between NMCs and the electrolyte, (iv) hindering phase transitions and impeding loss of lattice oxygen, (v) preventing microcracks in NMC particles to keep participation of most NMC material in lithiation/de-lithiation, and (vi) enhancing the rate capability of NMC cathodes. Finally, the personal perspectives on outlook are offered with an aim to stimulate further discussion and ideas on the rational design of coatings for durable and high-performance NMC cathodes for the next generation LIBs in the near future.
Qian Yang; Zhibin Wu; Zhijian Wang; Wei Liu; Jianwen Liu; Chuanqi Feng; Wei Sun; Haimin Zhao; Zaiping Guo
Abstract
Single-phase bi-metal oxides and sulfides have attracted considerable research interest recently for battery application because of their outstanding electrochemical properties, but there are few reports on single-phase bi-metal hydroxides in battery research. Herein, we pioneer the electrochemical study ...
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Single-phase bi-metal oxides and sulfides have attracted considerable research interest recently for battery application because of their outstanding electrochemical properties, but there are few reports on single-phase bi-metal hydroxides in battery research. Herein, we pioneer the electrochemical study of ZnSn(OH)6 nanocubes for lithium-ion battery application. The ZnSn(OH)6 nanocubes, synthesized by a facile hydrothermal method, can deliver a favorable specific discharge capacity of 599.3 mA h g -1 at 500 mA g -1 after 200 cycles and maintain good rate capability even at 2 A g -1 . The excellent electrochemical performance of these ZnSn(OH)6 nanocubes can be attributed to the synergetic Li storage capability of Zn and Sn elements with diverse electrochemical reactions, the small uniform nanocubes (30−50 nm) that alleviate the pulverization and cracking of the electrode and shorten electron/ion transport paths, and the good mechanical properties of ZnSn(OH)6, which facilitate maintenance of the structural integrity of the electrode during the Li + extraction/insertion process. Therefore, with these outstanding advantages, the ZnSn(OH)6 nanocubes could be one of the most promising anodes for advanced lithium-ion batteries.
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