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Silicon (Si) is a promising anode material for lithium-ion batteries but has long been suffering from low conductivity, drastic volume change, poor cycling performance, etc. Adding SiO, Al, etc. to form Si-based binary composite films can improve some properties but have to give up others. Here, we prepared a ternary Si–SiO–Al composite film anode by adding SiO and Al together into Si using magnetron sputtering. This film has an extraordinary combination of conductivity, specific capacity, cycling stability, rate performance, etc., when compared with its binary and unary counterparts. While both SiO and Al can separately mitigate anode cracking resulting from the huge volume expansion during the lithiation/delithiation cycling process, the synergetic effect of adding SiO and Al together to form a ternary composite film can produce much better results. This film maintains an island structure that can efficiently buffer the volume expansion during the cycling process, giving rise to superior cycling performance and excellent rate performance. In addition, the cosputtered Al improves the electrical conductivity of the anode at the same time. This unique combination of anode properties, together with the low cost, suggests that the Si–SiO–Al composite film has the potential to be commercialized as a binder-free anode for lithium-ion batteries. This work also provides an efficient means to modulate the anode properties with more degrees of freedom.

This manuscript focuses on how to improve the electronic conductivity and lithium-ion diffusivity of Li 4 Ti 5 O 12 thin films, which present a serious constraint to the development of the solid-state lithium-ion batteries. Given this understanding, we have found that creating amorphous structural features and hierarchical channels of thin films form a very simple yet effective approach to solve the problem. The unique structural features and high electrical conductivity of the as-prepared thin films result in high capacity (283.5 mAh g À1 at 10 mA cm À2 ) and good cyclic stability (%3 % capacity loss after 100 cycles at 10 mA cm À2 ). These important findings could open up new opportunities for Li 4 Ti 5 O 12 in constructing high-performance binder-free energy storage devices.Owing to their unique high-energy-density characteristics, Liion batteries (LIBs) originally developed for electronic devices are now being extended to a wide range of applications such as portable electronic devices, smart building control, smart medicine, and other ambient technologies. [1,2] As an alternative to traditional carbonaceous materials for anodes, Li 4 Ti 5 O 12 has attracted more attention as a promising anode material for Li-ion batteries because it exhibits excellent reversibility during the insertion/extraction process of Li ions with nearly zero volume change and a relatively high operating voltage (1.55 V vs. Li/Li + ), both of which ensure additional safety by avoiding lithium dendrites. [3][4][5][6][7][8] One of the drawbacks of the rate capability of Li 4 Ti 5 O 12 is that it is relatively low because of its poor electronic conductivity (< 10 À13 S cm À1) and sluggish lithium-ion diffusion. [9][10][11] Lithium transition-metal-oxide thin films have long been identified as good candidates for battery electrode materials. Thin film electrodes are useful for the improvement of the electrochemical properties of active materials that have poor conductivity. The thickness of thin films can be reduced to a value, at which the electrical conductivity does not significantly affect the electrochemical behavior.[12] Recent studies [13][14][15][16] report that Li 4 Ti 5 O 12 thin films for lithium-ion battery electrodes have been prepared by several methods: ion beam sputtering, sol-gel method, pulsed laser deposition, and radio frequency (RF) magnetron sputtering. Of these techniques, RF magnetron sputtering is an attractive technique to develop nanocomposite materials for powerful thin film LIBs and also to reveal the fundamental physical properties without the influence of binder phases. [17] The electrochemical behaviors of Li 4 Ti 5 O 12 discharged to 0 V are another way to increase the energy density and power density, which have been widely investigated. Borghols and his coworkers reported a size effect for the Li 4 + [20]In this article we focus on the amorphous Li 4 Ti 5 O 12 thin films deposited by RF magnetron sputtering. A powder target has been used as the sputtering source. To our knowledge, publications on amorphou...

A facile preparation method of a Si-based anode with excellent cycling property is urgently required in the process of preparing lithium-ion batteries (LIBs). Here, lithium titanate (LTO) matrix-supported nanocrystalline Si film is prepared by radio frequency (RF) magnetron cosputtering utilizing LTO and silicon (Si) targets as the sputtering source. LTO-supported nanocrystalline Si film electrodes revealed a repeatable specific capacity of 1200 mA h g −1 at 150 mA g −1 with a maintenance of more than 75% even after 800 cycles. The remarkable electrochemical properties of the LTO−Si composite films could be attributed to the LTO matrix, preventing the electrolyte from directly making contact with the nanocrystalline Si materials, alleviating the stress of the periodic volume change and further providing efficient and rapid pathways for lithium-ion transport. The results suggest that Si-based LTO composite films are prospective anodes for LIBs, with high capacities and long cycling stabilities.