Jingang Yang

LiNi0.5Mn1.5O4 Porous Nanorods as High-Rate and Long-Life Cathodes for Li-Ion Batteries

Spinel-type LiNi0.5Mn1.5O4 porous nanorods assembled with nanoparticles have been prepared and investigated as high-rate and long-life cathode materials for rechargeable lithium-ion batteries. One-dimensional porous nanostructures of LiNi0.5Mn1.5O4 with ordered P4332 phase were obtained through solid-state Li and Ni implantation of porous Mn2O3 nanorods that resulted from thermal decomposition of the chain-like MnC2O4 precursor. The fabricated LiNi0.5Mn1.5O4 delivered specific capacities of 140 and 109 mAh g(-1) at 1 and 20 C rates, respectively. At a 5 C cycling rate, a capacity retention of 91% was sustained after 500 cycles, with extremely low capacity fade (<1%) during the initial 300 cycles. The remarkable performance was attributed to the porous 1D nanostructures that can accommodate strain relaxation by slippage at the subunits wall boundaries and provide short Li-ion diffusion distance along the confined dimension.

Hydrogenated Uniform Pt Clusters Supported on Porous CaMnO3 as a Bifunctional Electrocatalyst for Enhanced Oxygen Reduction and Evolution

Hydrogenated uniform Pt clusters supported on porous CaMnO3 nanocomposites are synthesized and investigated as a new electrocatalytic material for oxygen reduction and evolution reactions. Due to the synergistic effect of Pt and CaMnO3, the nanocomposites exhibit superior activity and durability to the benchmark Pt/C catalyst.

Spinel LiNi0.5Mn1.5O4 cathode for rechargeable lithiumion batteries: Nano vs micro, ordered phase (P4332) vs disordered phase (Fd\(\bar 3\)m)

Since the high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is one of the most attractive cathode materials for lithium-ion batteries, how to improve the cycling and rate performance simultaneously has become a critical question. Nanosizing is a typical strategy to achieve high rate capability due to drastically shortened Li-ion diffusion distances. However, the high surface area of nanosized particles increases the side reaction with the electrolyte, which leads to poor cycling performance. Spinels with disordered structures could also lead to improved rate capability, but the cyclability is low due to the presence of Mn3+ ions. Herein, we systematically investigated the synergic interaction between particle size and cation ordering. Our results indicated that a microsized disordered phase and a nanosized ordered phase of LNMO materials exhibited the best combination of high rate capability and cycling performance.

Porous 0.2Li2MnO3·0.8LiNi0.5Mn0.5O2 nanorods as cathode materials for lithium-ion batteries

Porous 0.2Li2MnO3·0.8LiNi0.5Mn0.5O2 nanorods (LLNMO PNRs) assembled with nanoparticles have been prepared and investigated as cathode materials for rechargeable lithium-ion batteries. The LLNMO PNRs were obtained through solid-state Li and Ni implantation of porous Mn2O3 nanowires. Without surface modification, the as synthesized LLNMO PNRs exhibited superior capacity and rate capability to the counterpart bulk samples. An initial discharge capacity of 275 mA h g−1 could be delivered at 0.2 C rates, with about 90% capacity retention after 100 cycles. The remarkable performance was attributed to the porous 1D nanostructures that could buffer against the local volume change and shorten the Li-ion diffusion distance.

Intergrown LiNi0.5Mn1.5O4·LiNi1/3Co1/3Mn1/3O2 composite nanorods as high-energy density cathode materials for lithium-ion batteries

Intergrown LiNi0.5M1.5O4·LiNi1/3Co1/3Mn1/3O2 composite nanorods, which were synthesized by a simple self-supporting template method, delivered high energy density as cathode materials for lithium-ion batteries by taking advantage of both high voltage of the spinel LiNi0.5Mn1.5O4 and high Li+ storage capacity of the layered LiNi1/3Co1/3Mn1/3O2.