Browsing by Author "Singh, Neelam"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Electrodes with three dimensional current collectors and methods of making the same
    (2017-02-14) Galande, Charudatta; Singh, Neelam; Khatiwada, Suman; Ajayan, Pulickel M.; Rice University; United States Patent and Trademark Office
    In some embodiments, the present disclosure pertains to methods of forming electrodes on a surface. In some embodiments, the formed electrodes have a three-dimensional current collector layer. In some embodiments, the present disclosure pertains to the formed electrodes. In some embodiments, the present disclosure pertains to energy storage devices that contain the formed electrodes.
  • Thumbnail Image
    Item
    Methods of preventing corrosion of surfaces by application of energy storage-conversion devices
    (2017-05-02) Galande, Charudatta; Singh, Neelam; Khatiwada, Suman; Ajayan, Pulickel M.; Rice University; United States Patent and Trademark Office
    The present disclosure pertains to methods of protecting a surface (e.g., a metal surface) from corrosion by conformably attaching a hybrid device comprising at least one multilayer energy storage device and at least one energy conversion device. In some embodiments, the multilayer energy storage device is formed by the following steps: (1) applying a non-solid negative electrode current collector composition above the surface to form an negative electrode current collector layer above the surface; (2) applying a non-solid negative electrode composition above the negative electrode current collector layer to form an negative electrode layer above the negative electrode current collector layer; (3) applying a non-solid electrically insulating composition above the negative electrode layer to form an electrically insulating layer above the negative electrode layer; (4) applying a non-solid positive electrode composition above the electrically insulating layer to form a positive electrode layer above the electrically insulating layer; and (5) applying a non-solid positive electrode current collector composition above the positive electrode layer to form a positive electrode current collector layer above the positive electrode layer.
  • Thumbnail Image
    Item
    New Designs and architectures of electrochemical energy storage devices
    (2014-05-05) Singh, Neelam; Ajayan, Pulickel M.; Biswal, Sibani Lisa; Vajtai, Robert
    Superior performance of Li-ion batteries led an immediate adaptation of these batteries in portable electronics and demands have rapidly increased due adoption in electric vehicles. Development of novel form-factors of portable electronics and need for increasing the driving range of electric cars close to 500 miles per charge requires multifunctional batteries. Future generation batteries are expected to be an integrated part of device (car) structure. Current Li-ion batteries are multilayer device which are compact and volumetrically efficient but are limited to rectangular or cylindrical shapes, which constrains the form factors of devices. The advent of smart devices/objects has further generated interest in self-powered electronics with integrated storage. Such energy conversion-storage hybrids will require batteries that can be integrated directly into the object or surface of choice as well as with energy harvesting devices. This work focuses on the fabrication of unconventional battery designs that can be inconspicuously accommodated into devices and applications without constraining their form factor. The major challenge of seamless integration of these energy storage systems into electronic devices and household objects has been solved. The first part of this work explains the concept and development of novel fabrication process for the Li-ion batteries. We have developed a multi-step spray painting process to fabricate rechargeable Li-ion on a variety of materials such a metal, glass, ceramic and flexible polymer substrates. This fabrication process could have significant impact on the design, implementation and integration of energy storage devices as well as on the electronic device design. We have also explored the idea of spray painting solid Li-ion electrolytes based on lithium lanthanum zirconium oxide (LLZO) to solve the safety issues related to the liquid electrolyte used in spray paintable batteries. Use of solid state electrolyte is also expected to facilitate the fabrication of spray paintable batteries in ambient conditions. LLZO is a fast Li-ion conductor at room temperature and is one of the best choices for solid state electrolytes. We have studied the solution based processing of LLZO to fabricate thin, mechanically strong electrolyte membranes. We have also studied the chemical stability of this materials with common processing materials used in battery industry which led to the room temperature phase transformation in this material. Further, we have developed hybrid architecture of Li-ion battery electrode. A hybrid of Li-ion battery cathode (LiFePO4) and pseudo-capacitor material results in a very interesting characteristic of the electrode which ultimately gives an ultra-fast charge discharge capability to Li-ion batteries. The last part of this work explains the monolithic design for graphite oxide based supercapacitors. Graphite oxide is shown to possess good ionic conductivity in the presence of absorbed water which led to realization of fully functional monolith supercapacitor.
  • Thumbnail Image
    Item
    Paintable Battery
    (Springer, 2012) Singh, Neelam; Galande, Charudatta; Miranda, Andrea; Mathkar, Akshay; Gao, Wei; Reddy, Arava Leela Mohana; Vlad, Alexandru; Ajayan, Pulickel M.
    If the components of a battery, including electrodes, separator, electrolyte and the current collectors can be designed as paints and applied sequentially to build a complete battery, on any arbitrary surface, it would have significant impact on the design, implementation and integration of energy storage devices. Here, we establish a paradigm change in battery assembly by fabricating rechargeable Li-ion batteries solely by multi-step spray painting of its components on a variety of materials such as metals, glass, glazed ceramics and flexible polymer substrates. We also demonstrate the possibility of interconnected modular spray painted battery units to be coupled to energy conversion devices such as solar cells, with possibilities of building standalone energy capture-storage hybrid devices in different configurations.
  • Thumbnail Image
    Item
    Roll up nanowire battery from silicon chips
    (National Academy of Sciences, 2012) Vlad, Alexandru; Reddy, Arava Leela Mohana; Ajayan, Anakha; Singh, Neelam; Gohy, Jean-François; Melinte, Sorin; Ajayan, Pulickel M.
    Here we report an approach to roll out Li-ion battery components from silicon chips by a continuous and repeatable etch-infiltratepeel cycle. Vertically aligned silicon nanowires etched from recycled silicon wafers are captured in a polymer matrix that operates as Liþ gel-electrolyte and electrode separator and peeled off to make multiple battery devices out of a single wafer. Porous, electrically interconnected copper nanoshells are conformally deposited around the silicon nanowires to stabilize the electrodes over extended cycles and provide efficient current collection. Using the above developed process we demonstrate an operational full cell 3.4 V lithium-polymer silicon nanowire (LIPOSIL) battery which is mechanically flexible and scalable to large dimensions.