Apples to Apples comparison of Lead-Acid to Lithium Ion
The powerwall is an adaptation of Tesla's car battery systems for domestic use. The car power pack can be seen here: https://electrek.co/2016/02/03/tesla-battery-tear-down-85-kwh/

544kg; 85kWh; maximum power output 350kW. Obviously beats the lead-acid batteries by a long way, but requires more careful handling. Has to be kept cool and could potentially cause a nasty, unextinguishable fire if punctured. That's why it's kept in a titanium box. The use of lots of individual cells rather than one huge cell helps with cooling and safety.