Ruoxu Lin

Nickel Nanocone‐Array Supported Silicon Anode for High‐Performance Lithium‐Ion Batteries

The development of Li-ion batteries with high capacity, long lifespan, and fast charge/discharge rates is of great technological importance for future portable electronics, power tools, electric and hybrid vehicles, and renewable energies. [ 1–3 ] Silicon is a particularly appealing anode material for Li-ion batteries because of its high theoretical capacity of 4200 mAh g − 1 [ 4 ] and it has been the subject of extensive research efforts. [ 5 , 6 ] However, lithium alloying and de-alloying with Si are accompanied by an enormous volume change ( > 300%), which induces severe pulverization and electrical disconnection from the current collector. [ 7 ] This structural and electronic degradation thereby leads to drastic and fast capacity fading and hindrance of practical implementation. To overcome these drawbacks, one effective approach is to design powder-based composites (e.g., a Si-metal active/inactive matrix concept), [ 8 , 9 ] preferably Si-carbon composites which have been investigated for many years. [ 10–13 ] Previous research has shown improvement of the electrochemical performance of Si-based anodes but only to a limited extent. [ 6 ]

Facile fabrication of reticular polypyrrole–silicon core–shell nanofibers for high performance lithium storage

Silicon is the most promising anode material to replace graphite in lithium ion batteries due to its high theoretical capacity of 4200 mAh g−1. However, the enormous volume expansion of bulk Si during the lithiation process results in severe electrode degradation and capacity decay. Extensive research effort has been devoted to fabricating nanostructured Si-based materials to improve the capacity cycling stability. Herein, a facile two-step approach is developed for the fabrication of novel three-dimensional (3D) nanoarchitectures composed of polypyrrole–silicon (PPy–Si) core–shell nanofibers. Electropolymerized PPy nanofibers are utilized as the flexible substrate for the deposition of Si thin films via a chemical vapor deposition (CVD) procedure. In this well-designed configuration, the PPy nanofibers are favorable for facile charge delivery and gathering, while the porosity of the electrode can efficiently cushion the volume expansion of Si. The electrode delivers a high reversible capacity above 2800 mAh g−1 with appealing cycling stability (∼91% capacity retained after 100 cycles). The rate capability of the electrode is also remarkable with a high capacity and stability. It is revealed that the reticular nanofibers’ morphology is well preserved after repeated lithium insertion and extraction, which certainly indicates the superiority of our electrode design. This fabrication approach can also be extended to other electrodes for electrochemical energy conversion and storage.

Copper nanowires based current collector for light-weight and flexible composite silicon anode with high stability and specific capacity

A metal network fabricated by copper nanowires (CuNWs), synthesized in a facile way, is introduced to silicon composite anode as current collector for lithium-ion battery. The light and flexible sheet can act as the collector and the substrate, and improve the kinetic electron transport and the stability of composite anode. In this configuration, the composite anode exhibits a better capacity retention of 89.4% and a coulombic efficiency of ∼93% after 60 cycles (rate = 0.2C) compared to conventional composite thin film anode in which CuNWs are beneficial for electrochemical performances. There appears to be a promising improvement that the light-weighted anode can also be applied to meet the commercial requirement.

Fabrication of rutile TiO2 nanorod arrays on a copper substrate for high-performance lithium-ion batteries

A rutile TiO2 nanorod array has been successfully prepared on a flexible copper substrate and demonstrated as a high-performance anode material for lithium-ion batteries. The prepared materials exhibit excellent electrochemical performance, which depends crucially on the structural parameters and the large specific surface area of the array.

Cu@Sn nanostructures based on light-weight current collectors for superior reversible lithium ion storage

A binder-free method is applied to avoid the huge irreversible capacity of Sn-based composite anodes in this paper. We report two types of copper-based current collector: (i) a light and flexible current collector, which is fabricated from copper nanowires (CuNWs), and (ii) Cu foam with copper nanowires grown on it. The charge capacity of the thin CuNW sheet based Sn–Cu composite anode remains above 760 mA h g−1 after 60 cycles with a relatively stable coulombic efficiency fluctuating around 97%. The Cu foam based composite anode also shows a good capacity retention of 79.8% after the same test, compared with the Cu foil based anode. According to the good rate performance and the light weight of the composite electrode, the CuNW sheet based current collector may be a promising material in energy fields in the future.