Moli Energy (1990) Limited

Qiming Zhong

Ulrich Von Sacken

Jeffery R Dahn

Jeffrey R Dahn

Alfred M Wilson

Jiayu Simon Xue

Tao Zheng

Yinghu Liu

Yuan Gao

Arman Bonakdarpour

Carbonaceous insertion compounds and methods for preparation are described wherein the compounds comprise a highly disordered, impurity free, hard pre-graphitic carbonaceous host. Carbonaceous insertion compounds can be prepared which have large reversible capacity for lithium yet low irreversible capacity and voltage hysteresis. Such insertion compounds can be prepared by simple pyrolysis of suitable epoxy, phenolic resin, or carbohydrate precursors at an appropriate temperature. These insertion compounds may be suitable for use as high capacity anodes in lithium ion batteries.

Pre-graphitic carbonaceous insertion compounds and use as anodes in rechargeable batteries

The loss in delivered capacity as a function of the number of charge/discharge cycles in non-aqueous rechargeable lithium batteries can be reduced by exposing the electrolyte therein to P.sub.2 O.sub.5. The exposure to P.sub.2 O.sub.5 can be accomplished by incorporating P.sub.2 O.sub.5 in either electrode or other locations that contact the electrolyte. Alternately, the electrolyte can be exposed prior to assembling the battery. The invention is particularly suited to certain lithium ion rechargeable battery electrochemistries.

Use of P.sub.2 O.sub.5 in non-aqueous rechargeable lithium batteries

Spinel insertion compounds Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, 0&lt;x&lt; about 0.33, 0.ltoreq.y&lt;about 1, can have relatively low surface area at relatively large values of x when prepared with a novel two step heating method. Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 is first prepared between a critical temperature, T.sub.c, and about 900.degree. C. Then, a lithium salt is mixed therewith and reacted at a temperature between about 400.degree. C. and T.sub.c. These compounds are suitable for use as a cathode in a lithium battery. The use of LiCl as the lithium salt can provide improved cycle life results in such a battery.

Method for preparing Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 for use in

The viscosity of certain non-aqueous electrolytes comprising a first lithium salt which can gel on the addition of P.sub.2 O.sub.5 can be reduced substantially by incorporating therein a small amount of a suitable viscosity reducing salt. In particular, the viscosity of a LiPF.sub.6 salt based electrolyte can be reduced by orders of magnitude by incorporating a small amount of LiBF.sub.4 therein. Such electrolytes are suitable for use in lithium ion batteries.

Low viscosity electrolyte comprising P.sub.2 O.sub.5 for use in

Insertion compounds having the formula Li.sub.x+y M.sub.z Mn.sub.2-y-z O.sub.4 wherein the crystal structure is spinel-like, M is a transition metal, 0.ltoreq.x&lt;1, 0.ltoreq.y&lt;0.33, and 0&lt;z&lt; about 1, can reversibly insert significant amounts of lithium at potentials greater than about 4.5 volts versus Li/Li.sup.+. In particular, M can be Ni or Cr. The reversible amount of lithium at such voltages can be greater for greater values of z. Such insertion compounds are suitable cathode materials for high voltage lithium batteries.

Growing community of inventors

Coquitlam, Canada

Qiming Zhong