▎ 摘　　要

NOVELTY - An alumina of fibrous form or needle shape comprises surface which is coated by graphene or aluminum-nitride compound. USE - An alumina for manufacture of sheet-like alumina-sintered compact coated with graphene (claimed). Can be used in a battery. ADVANTAGE - The alumina has large surface area with unprecedented high electrical and thermal conductivity with increased strength. The battery which uses the alumina has improved capacity and lifetime. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) manufacture of alumina coated with graphene which involves preparing alumina particle or hydrated-alumina particles of fibrous form or needle shape and hydrocarbon by chemical vapor deposition at 500-1200 degrees C; (2) manufacture of sheet-like alumina-sintered compact coated with graphene which involves coating alumina particle or hydrated-alumina particles of fibrous form or needle shape on heat-resistant substrate or synthetic resin sheets, and a hydrocarbon by chemical vapor deposition at 500-1200 degrees C; (3) manufacture of alumina coated with graphene which involves mixing alumina particle or hydrated-alumina particles of fibrous form or needle shape with synthetic resin, and a hydrocarbon, and heat-processing at 500-1200 degrees C; (4) manufacture of alumina coated with aluminum-nitride compound which involves coating alumina and ammonia with graphene obtained by manufacturing alumina particle or hydrated-alumina particles of fibrous form or needle shape, and hydrocarbon by chemical vapor deposition at 500-1200 degrees C and heat-processing at 500-1200 degrees C; (5) manufacture of sheet-like alumina-sintered compact coated with aluminum-nitride compound which involves coating alumina particle or hydrated-alumina particles of fibrous form or needle shape on a heat-resistant substrate or synthetic resin sheets, and a hydrocarbon, by chemical vapor deposition at 500-1200 degrees C and heat-processing at 500-1200 degrees C; and (6) electrical-conductive or heat-conductive composition comprising the alumina.