LiV2O5 - An under-rated active material for Li-ion applications

Gamma-LiV2O5 may represent an inexpensive and safe cathode alternate to LiFePO4 for large format Li-ion applications. Preliminary analysis suggests that this active material should cost less than $20/kg to mass produce.

Further information may be found here:

Perfomance Evaluation of LiV2O5 - J. Barker et al. (2003)

In summary, the electrochemical evaluation of Gamma-LiV2O5 indicates that the active material is capable of cycling at a specific capacity of 130 mAh/g - a performance that compares favorably with the theoretical figure of 142 mAh/g. This material utilization corresponds to the reversible cycling of x = 0.92 in Gamma-LixV2O5 – a remarkably high charge efficiency. The average discharge voltage is around 3.4 V vs Li. High-resolution electrochemical evaluation indicates the lithium insertion reactions may be characterized in two separate but highly reversible processes.

The long-term electrochemical stability of the active material has been demonstrated clearly by lifetime cycling experiments in a graphite based Li-ion configuration. The cells show low first cycle charge inefficiency as well as demonstrating two hundred charge-discharge cycles with relatively low capacity fade behavior.

Jerry

Lithium: The Key Resource

As we fast move towards an economy dominated by electric vehicles powered by Li-ion battery technology, the cost and abundance of lithium will become a major political and commercial issue. Some recent reports have questioned the long term viability of lithium.

A report by the Technology Review summarizes the latest position. The Review expects demand for the metal to double in the next 10 years, and Bolivia, with an untapped resource estimated at nine million tons by the U.S. Geological Survey, is being called a potential "Saudi Arabia of lithium."

More information (with great pictures) may be found here:

The Lithium Rush

Companies involved in energy storage will need to continually adopt to these new market conditions, and the exploration of novel technologies not based on lithium will need to be examined.

Jerry

Sodium-ion Batteries: Interest Grows

Following on from my post last month regarding the upsurge of interest in Sodium-ion technology, 44 Tech, a start-up company based in Pittsburgh, PA, will receive $5 million from the U.S. Department of Energy, as part of the 2009 Recovery Act, to develop aqueous sodium-ion batteries. These cells will differ from the non-aqueous counterparts described by me in an earlier post, in that they will operate at much lower voltage (due to the limited voltage stability window of the electrolyte). On the positive side, if these systems can be demonstrated successfully, they may prove extremely safe and inexpensive.

The full story may be found here:

Sodium-ion Cells for Cheap Energy Storage

Jerry

Imara: Battery Start-up Closes

The GreenTechMedia website has reported that Imara, the Li-ion battery start-up company located in Menlo Park, California, has ceased operations.

The report can be found here:

GreenTechMedia reports the demise of Imara

Imara's company website can be found here:

Imara Corporation

Recent reports have suggested that the company has experienced a delay in ramping up operations and could not line up investors to build a factory. Imara had started to make prototype and sample quantities of batteries in its Menlo Park, Calif. facility.

Imara employed 38 scientists and engineers. It will try to sell its assets and intellectual property but right now the company is shut down.

GreenTechMedia speculates that the demise of Imara could portend bad news for other green startups. The battery business is generally dominated by large, Asian manufacturers and many of the grants from the Department of Energy did go to joint ventures partly owned by foreign companies. Two joint ventures with South Korean partners – Dow Kokam and Compact Power – received $312.4 million earlier this year from the DOE. Only a few U.S.-based lithium-ion battery makers such as A123 Systems and EnerDel have received stimulus funds.

Jerry

Nexeon - Unique Silicon Li-ion Anode Technology

Nexeon, the UK-based Li-ion battery materials and licensing company has launched its new website:

Nexeon - Unique Silicon Li-ion Anode Technology

The company is developing nano-structured silicon materials for incorporation into next generation lithium-ion batteries.

The website reports that recent tests have shown that low first cycle loss and extended cycle life can be achieved using Nexeon’s silicon anode materials at a lower cost than graphite for a given capacity. The low-cost silicon anode technology demonstrates a clear commercial viability compared to other more expensive approaches such as silicon nano-fibres, ribbons or tubes.

Nexeon has developed a number of materials, proprietary processes and equipment for producing the material and for making electrodes. It has 12 patent families in progress worldwide, the first of which is granted and others which are now being published. This includes patents on high-aspect ratio silicon materials and the use of such materials in lithium ion batteries.

Focus: Titanate Cathode Materials for Li-ion Batteries

Lithium metal titanate and zironate compounds phases are currently experiencing significant interest as potential new cathode active materials for next generation Li-ion batteries. Jerry Barker (and co-workers) is the named inventor on the issued US patents covering the use of LiMTiO4 and LiMZrO4 (where M= +3 oxidation state transition metal, US#6,103,419); and Li2MTiO4 and Li2MZrO4 (where M = +2 oxidation state transition metal, US#6,720,113) materials; in these energy storage applications.

Further information about these materials and their performance in Li-ion cells may be found in the issued US patents. Links to these patents may be found here:

J.Barker et al. US#6103419; LiMTiO4 and LiMZrO4 Cathode Materials (M = V, Cr, Fe, Mn etc.)

J.Barker et al. US#6720113; Li2MTiO4 and Li2MZrO4 Cathode Materials (M= Fe, Mn, Ni, Co etc.)

The US patent covering the novel synthesis method for some of these materials may be found here:

J.Barker et al. US#6706445; Titanate and Zirconate Synthesis Method

Jerry

Focus: Hybrid-ion Batteries

Hybrid-ion cells are a new and exciting concept in energy storage technology.

Background: During charge and discharge of conventional Li-ion cells, lithium ions are shuttled back-and-forth between the two insertion-based electrode materials. These processes are well understood and characterized.

In hybrid-ion cells, a non-lithium containing cathode material is coupled with a suitable lithium-based anode material such as graphite, hard carbon or lithium titanate, Li4/3Ti5/3O4. This simple but novel approach greatly increases the number of commercially useful cathode materials. By comparison with lithium, only a limited number of sodium insertion materials have been properly characterized for use in energy storage devices.

The electrochemical system is completed by the use of a conventional lithium-based non-aqueous electrolyte. During the initial charge process, Na ions are extracted from the cathode while concurrent lithium ion insertion occurs at the negative electrode. During subsequent cell discharge, lithium ions are extracted from the negative electrode while a mixed sodium/lithium insertion reaction occurs at the positive electrode. These reactions are fully reversible and in prototype cells very long lifetimes have been demonstrated. All the electroactive lithium ions in the electrochemical system originate from the electrolyte phase.

More details on this novel energy storage concept may be found below.

Hybrid-ion: A Lithium-ion Cell based on a Sodium Insertion Material.

J. Barker et al., ESL 9, A190, (2006)

Li4/3Ti5/3O4//Na3V2(PO4)2F3: An example of a Hydrid-ion Cell based on a non-graphitic anode

J.Barker et al., JES 154, A882, (2007)

Jerry

Focus: Sodium-ion Batteries

In my opinion, sodium-ion batteries represent an important energy storage alternative to conventional lithium-ion technology. Based on initial data these batteries should offer similar electrochemical characteristics to their lithium counterparts. In addition, they may provide some significant performance advantages such as: lower material costs and improved safety performance. These properties will be particularly important in future large format uses such as automotive (EV/PHEV) and stationary applications.

Based on these facts it is somewhat surprising that so little research effort has been dedicated to the commercial development of these energy storage systems. Part of the problem is the identification of suitable Na insertion anode materials. Unfortunately, graphite (the preferred negative electrode materials in Li-ion cells) does not allow significant Na ion uptake. Recent work, however has demonstrated significant amounts of sodium may be reversible cycled in disordered, hard carbon hosts. This has allowed the creation of some novel sodium-ion chemistries.

For instance, we recently reported the preliminary performance characteristics of the Hard Carbon//NaVPO4F cell. The abstract to the work may be found here:

Barker et al; A Sodium-ion Cell based on the Fluorophosphate Compound NaVPO4F

Further details on this, and other polyanion based sodium-ion cells may be found here:

Barker et al; US Patent #6872492

Jerry

LiMnPO4 News: HPL acquired by the Dow Chemical Company

Related to the discussions regarding the LiMnPO4 active material:

Green Car Congress (Nov. 12, 2009) reports that the Dow Chemical Company has announced the transfer to Dow of collective assets from High Power Lithium, HPL. HPL was spun out from Professor Graetzel’s laboratory at the EPFL (Ecole Polytechnique Federale de Lausanne, Switzerland) in 2003 and is focused on the development of nano-structured metal oxide energy storage materials and novel electrolytes for use in next generation lithium ion batteries.

HPL brings synthesis and development of novel nano-materials, the ability to process and optimize nano-materials for use in battery electrodes and cells, comprehensive physical and electrochemical characterization facilities and screening and development of novel electrolytes and systems.

More information may be found here:

Dow Chemical Company Press Release:

http://news.dow.com/dow_news/corporate/2009/20091112c.htm

High Power Lithium website:

http://www.highpowerlithium.com/

Jerry

LiMnPO4 - The Thermal Instability of the De-lithiated Phase

Further to the entry below - the paper by Guoying Chen and Thomas Richardson (Lawrence Berkeley Labs.) on the Thermal Instability of Olivine-type LiMnPO4 Cathodes has now been published in the J. Power Sources. The abstract may be found here:

http://dx.doi.org/10.1016/j.jpowsour.2009.08.046

In essence, the paper reports that de-lithiated LixMnPO4 is thermally unstable and reactive toward a lithium-ion electrolyte. Furthermore, the total evolved heat is 884 J g−1, comparable to that produced under similar conditions by charged LiCoO2 electrodes.

This is bad news for organizations developing next generation lithium-ion batteries based on this material and comes as somewhat of a surprise. Most commentators in this sector predicted that the thermal behaviour of the LiMnPO4 olivine phase would be similar to the iron analogue, LiFePO4.