Decorating Phosphorus Anode with SnO2 Nanoparticles To Enhance Polyphosphides Chemisorption for High-Performance Lithium-Ion Batteries.

Phosphorus has been regarded as one of the most promising next-generation lithium-ion battery anode materials, because of its high theoretical specific capacity and safe working potential. However, the shuttle effect and sluggish conversion kinetics hamper its practical application. To overcome these limitations, we decorated SnO2 nanoparticles at the surface of phosphorus using an electrostatic self-assembly method, in which SnO2 can participate in the discharge/charge reaction, and the Li2O formed can chemically adsorb and suppress the shuttle of soluble polyphosphides across the separator. Additionally, the Sn/Li-Sn alloy can enhance the electrical conductivity of the overall electrode. Meanwhile, the similar volume changes and simultaneous lithiation/delithiation process in phosphorus and SnO2/Sn are beneficial for avoiding additional particle damage near two-phase boundaries. Consequently, this hybrid anode exhibits a high reversible capacity of ∼1180.4 mAh g-1 after 120 cycles and superior high-rate performance with ∼78.5% capacity retention from 100 to 1000 mA g-1.

Surficial Oxidation of Phosphorus for Strengthening Interface Interaction and Enhancing Lithium-Storage Performance.

By virtue of high theoretical capacity and appropriate lithiation potential, phosphorus is considered as a prospective next-generation anode material for lithium-ion batteries. However, there are some problems hampering its practical application, such as low ionic conductivity and serious volume expansion. Herein, we demonstrated an in situ preoxidation strategy to build a oxidation function layer at phosphorus particle. The oxide layer not only acted as a protective layer to prolong the storage time of phosphorus anode in air but also carbonized N-methyl pyrrolidone and poly (vinylidene fluoride), strengthening the interfacial interaction between phosphorus particles and binder. The oxide layer further induced the formation of a stable solid electrolyte interface with high lithium-ion conductivity. The oxidized P-CNT maintained high specific capacity of 1306 mAh g-1 and 89% capacity after 100 cycles, much higher than that of pristine P-CNT (17.1%). The strategy of in situ oxidation is facile and conducive to the practical application of phosphorus-based anodes.

K2Ti6O13/carbon core-shell nanorods as a superior anode material for high-rate potassium-ion batteries.

Bunches of oriented K2Ti6O13 nanorods coated by a thin carbon layer (4-7 nm) were prepared by combining hydrothermal and heat treatment in sequence. The K2Ti6O13 nanorods possess long- and short-axis crystal orientations of <010> and <001>, respectively, contributing to fast K+ diffusion, and the carbon-coating layer improves the electron conductivity. In addition, the obtained K2Ti6O13/carbon has a high compaction density, which is beneficial for realizing high volumetric specific capacity. When evaluated as a potassium-ion battery anode, the nanorods demonstrated a superior rate capability (122.5, 104.3, 92.3, 78.6 and 65.1 mA h g-1 at current densities of 20, 50, 100, 200 and 500 mA g-1, respectively), a favourable cycle life (118.5 mA h g-1 at 25 mA g-1 for 200 cycles) and high capacity retention.