Nanostructured high-energy cathode materials for advanced lithium batteries

Abstract

Nickel-rich layered lithium transition-metal oxides, LiNi(1-x)M(x)O(2) (M = transition metal), have been under intense investigation as high-energy cathode materials for rechargeable lithium batteries because of their high specific capacity and relatively low cost. However, the commercial deployment of nickel-rich oxides has been severely hindered by their intrinsic poor thermal stability at the fully charged state and insufficient cycle life, especially at elevated temperatures. Here, we report a nickel-rich lithium transition-metal oxide with a very high capacity (215 mA h g(-1)), where the nickel concentration decreases linearly whereas the manganese concentration increases linearly from the centre to the outer layer of each particle. Using this nano-functional full-gradient approach, we are able to harness the high energy density of the nickel-rich core and the high thermal stability and long life of the manganese-rich outer layers. Moreover, the micrometre-size secondary particles of this cathode material are composed of aligned needle-like nanosize primary particles, resulting in a high rate capability. The experimental results suggest that this nano-functional full-gradient cathode material is promising for applications that require high energy, long calendar life and excellent abuse tolerance such as electric vehicles.

Defect-induced plating of lithium metal within porous graphene networks

“…By contrast, the practically realizable capacities and energy densities for LiMnO 2 , LiFePO 4 and LiCoO 2 cathodes lie [12][13][14] in the 110-170 mAh g À 1 and 470-545 Wh kg À 1 range, respectively. A comparison of the specific capacities versus cycle index obtained from the lithiated PGN cathode and conventional cathode materials [47][48][49][50] has been provided in Fig. 6c.…”

“…The graphene network not only acts as a caged entrapment for lithium metal (that prevents dendritic growth) but also provides a conductive network for efficient electron transfer (no current collectors are used), thereby offering significant improvements over other less-conductive cathodes that often require additional doping 47 . The successful demonstration of a pouch cell (in a full-cell configuration) with PGN anodes and Li-PGN cathodes indicates the feasibility of an all-carbon lithium battery, which could greatly simplify the battery chemistry.…”

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications

“…For storing renewable energy, reliabilty and cost are more important 2. While many research interests have been focused on materials chemistry,3 and electrolytes,4 the understanding of their derived interfaces has made much less progress due to the complexity of electrolyte decomposition in dynamic conditions and on various substrates with different surface properties. However, interfaces do play a critically important role in determining the mass flow and electrochemical kinetics, and thus the power, stability, and safety of LIBs 4…”

Multishelled Ni‐Rich Li(NixCoyMnz)O2 Hollow Fibers with Low Cation Mixing as High‐Performance Cathode Materials for Li‐Ion Batteries

“…In particular, the Ni‐rich oxides such as Li(Ni x Co y Mn z )O 2 ( x ≥ 0.5) have attracted intense research attention,3 since they provide very high specific capacity, ≈212 mAh g −1 for x = 0.8 and 220 mAh g −1 for x = 0.86. However, unlike low Ni content oxides which generally exhibit outstanding stabilities,2 Ni‐rich oxides suffer inherent drawbacks including poor cycle life and rate performance due to low Li diffusion rates caused by cation mixing.…”